Produced by Sue Asscher





BRAMBLE-BEES AND OTHERS

by J. HENRI FABRE




TRANSLATED BY ALEXANDER TEIXEIRA DE MATTOS, F.Z.S.

TRANSLATOR'S NOTE.

In this volume I have collected all the essays on Wild Bees scattered
through the "Souvenirs entomologiques," with the exception of those on
the Chalicodomae, or Mason-bees proper, which form the contents of a
separate volume entitled "The Mason-bees."

The first two essays on the Halicti (Chapters 12 and 13) have already
appeared in an abbreviated form in "The Life and Love of the Insect,"
translated by myself and published by Messrs. A. & C. Black (in America
by the Macmillan Co.) in 1911. With the greatest courtesy and kindness,
Messrs. Black have given me their permission to include these two
chapters in the present volume; they did so without fee or consideration
of any kind, merely on my representation that it would be a great pity
if this uniform edition of Fabre's Works should be rendered incomplete
because certain essays formed part of volumes of extracts previously
published in this country. Their generosity is almost unparalleled in my
experience; and I wish to thank them publicly for it in the name of
the author, of the French publishers and of the English and American
publishers, as well as in my own.

Of the remaining chapters, one or two have appeared in the "English
Review" or other magazines; but most of them now see the light in
English for the first time.

I have once more, as in the case of "The Mason-bees," to thank Miss
Frances Rodwell for the help which she has given me in the work
of translation and research; and I am also grateful for much kind
assistance received from the staff of the Natural History Museum and
from Mr. Geoffrey Meade-Waldo in particular.

ALEXANDER TEIXEIRA DE MATTOS.

Chelsea, 1915.




CONTENTS.

TRANSLATOR'S NOTE.

CHAPTER 1. BRAMBLE-DWELLERS.

CHAPTER 2. THE OSMIAE.

CHAPTER 3. THE DISTRIBUTION OF THE SEXES.

CHAPTER 4. THE MOTHER DECIDES THE SEX OF THE EGG.

CHAPTER 5. PERMUTATIONS OF SEX.

CHAPTER 6. INSTINCT AND DISCERNMENT.

CHAPTER 7. ECONOMY OF ENERGY.

CHAPTER 8. THE LEAF-CUTTERS.

CHAPTER 9. THE COTTON-BEES.

CHAPTER 10. THE RESIN-BEES.

CHAPTER 11. THE POISON OF THE BEE.

CHAPTER 12. THE HALICTI: A PARASITE.

CHAPTER 13. THE HALICTI: THE PORTRESS.

CHAPTER 14. THE HALICTI: PARTHENOGENESIS.

INDEX.




CHAPTER 1. BRAMBLE-DWELLERS.

The peasant, as he trims his hedge, whose riotous tangle threatens to
encroach upon the road, cuts the trailing stems of the bramble a foot
or two from the ground and leaves the root-stock, which soon dries up.
These bramble-stumps, sheltered and protected by the thorny brushwood,
are in great demand among a host of Hymenoptera who have families to
settle. The stump, when dry, offers to any one that knows how to use it
a hygienic dwelling, where there is no fear of damp from the sap; its
soft and abundant pith lends itself to easy work; and the top offers a
weak spot which makes it possible for the insect to reach the vein of
least resistance at once, without cutting away through the hard
ligneous wall. To many, therefore, of the Bee and Wasp tribe, whether
honey-gatherers or hunters, one of these dry stalks is a valuable
discovery when its diameter matches the size of its would-be
inhabitants; and it is also an interesting subject of study to the
entomologist who, in the winter, pruning-shears in hand, can gather in
the hedgerows a faggot rich in small industrial wonders. Visiting the
bramble-bushes has long been one of my favourite pastimes during the
enforced leisure of the wintertime; and it is seldom but some new
discovery, some unexpected fact, makes up to me for my torn fingers.

My list, which is still far from being complete, already numbers nearly
thirty species of bramble-dwellers in the neighbourhood of my house;
other observers, more assiduous than I, exploring another region and one
covering a wider range, have counted as many as fifty. I give at foot an
inventory of the species which I have noted.

(Bramble-dwelling insects in the neighbourhood of Serignan [Vaucluse]:

     1. MELLIFEROUS HYMENOPTERA.
     Osmia tridentata, DUF. and PER.
     Osmia detrita, PEREZ.
     Anthidium scapulare, LATR.
     Heriades rubicola, PEREZ.
     Prosopis confusa, SCHENCK.
     Ceratina chalcites, GERM.
     Ceratina albilabris, FAB.
     Ceratina callosa, FAB.
     Ceratina coerulea, VILLERS.

     2. HUNTING HYMENOPTERA.
     Solenius vagus, FAB. (provisions, Diptera).
     Solenius lapidarius, LEP. (provisions, Spiders?).
     Cemonus unicolor, PANZ. (provisions, Plant-lice).
     Psen atratus (provisions, Black Plant-lice).
     Tripoxylon figulus, LIN. (provisions, Spiders).
     A Pompilus, unknown (provisions, Spiders).
     Odynerus delphinalis, GIRAUD.

     3. PARASITICAL HYMENOPTERA.
     A Leucopsis, unknown (parasite of Anthidium scapulare).
     A small Scoliid, unknown (parasite of Solenius vagus).
     Omalus auratus (parasite of various bramble-dwellers).
     Cryptus bimaculatus, GRAV. (parasite of Osmia detrita).
     Cryptus gyrator, DUF. (parasite of Tripoxylon figulus).
     Ephialtes divinator, ROSSI (parasite of Cemonus unicolor).
     Ephialtes mediator, GRAV. (parasite of Psen atratus).
     Foenus pyrenaicus, GUERIN.
     Euritoma rubicola, J. GIRAUD (parasite of Osmia detrita).

     4. COLEOPTERA.
     Zonitis mutica, FAB. (parasite of Osmia tridentata).

Most of these insects have been submitted to a learned expert, Professor
Jean Perez, of Bordeaux. I take this opportunity of renewing my thanks
for his kindness in identifying them for me.--Author's Note.)

They include members of very diverse corporations. Some, more
industrious and equipped with better tools, remove the pith from the dry
stem and thus obtain a vertical cylindrical gallery, the length of which
may be nearly a cubit. This sheath is next divided, by partitions, into
more or less numerous storeys, each of which forms the cell of a larva.
Others, less well-endowed with strength and implements, avail themselves
of the old galleries of other insects, galleries that have been
abandoned after serving as a home for their builder's family. Their only
work is to make some slight repairs in the ruined tenement, to clear the
channel of its lumber, such as the remains of cocoons and the litter of
shattered ceilings, and lastly to build new partitions, either with
a plaster made of clay or with a concrete formed of pith-scrapings
cemented with a drop of saliva.

You can tell these borrowed dwellings by the unequal size of the
storeys. When the worker has herself bored the channel, she economizes
her space: she knows how costly it is. The cells, in that case, are all
alike, the proper size for the tenant, neither too large nor too small.
In this box, which has cost weeks of labour, the insect has to house the
largest possible number of larvae, while allotting the necessary amount
of room to each. Method in the superposition of the floors and economy
of space are here the absolute rule.

But there is evidence of waste when the insect makes use of a bramble
hollowed by another. This is the case with Tripoxylon figulus. To obtain
the store-rooms wherein to deposit her scanty stock of Spiders, she
divides her borrowed cylinder into very unequal cells, by means of
slender clay partitions. Some are a centimetre (.39 inch.--Translator's
Note.) deep, the proper size for the insect; others are as much as two
inches. These spacious rooms, out of all proportion to the occupier,
reveal the reckless extravagance of a casual proprietress whose
title-deeds have cost her nothing.

But, whether they be the original builders or labourers touching up the
work of others, they all alike have their parasites, who constitute
the third class of bramble-dwellers. These have neither galleries to
excavate nor victuals to provide; they lay their egg in a strange cell;
and their grub feeds either on the provisions of the lawful owner's
larva or on that larva itself.

At the head of this population, as regards both the finish and the
magnitude of the structure, stands the Three-pronged Osmia (Osmia
tridentata, DUF. and PER.), to whom this chapter shall be specially
devoted. Her gallery, which has the diameter of a lead pencil, sometimes
descends to a depth of twenty inches. It is at first almost exactly
cylindrical; but, in the course of the victualling, changes occur which
modify it slightly at geometrically determined distances. The work of
boring possesses no great interest. In the month of July, we see the
insect, perched on a bramble-stump, attack the pith and dig itself a
well. When this is deep enough, the Osmia goes down, tears off a few
particles of pith and comes up again to fling her load outside. This
monotonous labour continues until the Bee deems the gallery long enough,
or until, as often happens, she finds herself stopped by an impassable
knot.

Next comes the ration of honey, the laying of the egg and the
partitioning, the last a delicate operation to which the insect proceeds
by degrees from the base to the top. At the bottom of the gallery, a
pile of honey is placed and an egg laid upon the pile; then a partition
is built to separate this cell from the next, for each larva must
have its special chamber, about a centimetre and a half (.58
inch.--Translator's Note.) long, having no communication with the
chambers adjoining. The materials employed for this partition are
bramble-sawdust, glued into a paste with the insects' saliva. Whence are
these materials obtained? Does the Osmia go outside, to gather on the
ground the rubbish which she flung out when boring the cylinder? On the
contrary, she is frugal of her time and has better things to do than to
pick up the scattered particles from the soil. The channel, as I said,
is at first uniform in size, almost cylindrical; its sides still retain
a thin coating of pith, forming the reserves which the Osmia, as a
provident builder, has economized wherewith to construct the partitions.
So she scrapes away with her mandibles, keeping within a certain radius,
a radius that corresponds with the dimensions of the cell which she is
going to build next; moreover, she conducts her work in such a way as to
hollow out more in the middle and leave the two ends contracted. In this
manner, the cylindrical channel of the start is succeeded, in the worked
portion, by an ovoid cavity flattened at both ends, a space resembling a
little barrel. This space will form the second cell.

As for the rubbish, it is utilized on the spot for the lid or cover
that serves as a ceiling for one cell and a floor for the next. Our own
master-builders could not contrive more successfully to make the best
use of their labourers' time. On the floor thus obtained, a second
ration of honey is placed; and an egg is laid on the surface of the
paste. Lastly, at the upper end of the little barrel, a partition is
built with the scrapings obtained in the course of the final work on the
third cell, which itself is shaped like a flattened ovoid. And so the
work goes on, cell upon cell, each supplying the materials for the
partition separating it from the one below. On reaching the end of the
cylinder, the Osmia closes up the case with a thick layer of the same
mortar. Then that bramble-stump is done with; the Bee will not return
to it. If her ovaries are not yet exhausted, other dry stems will be
exploited in the same fashion.

The number of cells varies greatly, according to the qualities of the
stalk. If the bramble-stump be long, regular and smooth, we may count
as many as fifteen: that, at least, is the highest figure which my
observations have supplied. To obtain a good idea of the internal
distribution, we must split the stalk lengthwise, in the winter, when
the provisions have long been consumed and when the larvae are wrapped
in their cocoons. We then see that, at regular intervals, the case
becomes slightly narrower; and in each of the necks thus formed a
circular disk is fixed, a partition one or two millimetres thick.
(.039 to.079 inch.--Translator's Note.) The rooms separated by these
partitions form so many little barrels or kegs, each compactly filled
with a reddish, transparent cocoon, through which the larva shows,
bent into a fish-hook. The whole suggests a string of rough, oval amber
beads, touching at their amputated ends.

In this string of cocoons, which is the oldest, which the youngest? The
oldest is obviously the bottom one, the one whose cell was the first
built; the youngest is the one at the top of the row, the one in the
cell last built. The oldest of the larvae starts the pile, down at the
bottom of the gallery; the latest arrival ends it at the top; and those
in between follow upon one another, according to age, from base to apex.

Let us next observe that there is no room in the shaft for two Osmiae at
a time on the same level, for each cocoon fills up the storey, the keg
that belongs to it, without leaving any vacant space; let us also remark
that, when they attain the stage of perfection, the Osmiae must all
emerge from the shaft by the only orifice which the bramble-stem
boasts, the orifice at the top. There is here but one obstacle, easy
to overcome: a plug of glued pith, of which the insect's mandibles make
short work. Down below, the stalk offers no ready outlet; besides, it is
prolonged underground indefinitely by the roots. Everywhere else is the
ligneous fence, generally too hard and thick to break through. It is
inevitable therefore that all the Osmiae, when the time comes to quit
their dwelling, should go out by the top; and, as the narrowness of
the shaft bars the passage of the preceding insect as long as the next
insect, the one above it, remains in position, the removal must begin at
the top, extend from cell to cell and end at the bottom. Consequently,
the order of exit is the converse to the order of birth: the younger
Osmiae leave the nest first, their elders leave it last.

The oldest, that is to say, the bottom one, was the first to finish her
supply of honey and to spin her cocoon. Taking precedence of all her
sisters in the whole series of her actions, she was the first to burst
her silken bag and to destroy the ceiling that closes her room: at
least, that is what the logic of the situation takes for granted. In
her anxiety to get out, how will she set about her release? The way
is blocked by the nearest cocoons, as yet intact. To clear herself a
passage through the string of those cocoons would mean to exterminate
the remainder of the brood; the deliverance of one would mean the
destruction of all the rest. Insects are notoriously obstinate in their
actions and unscrupulous in their methods. If the Bee at the bottom of
the shaft wants to leave her lodging, will she spare those who bar her
road?

The difficulty is great, obviously; it seems insuperable. Thereupon we
become suspicious: we begin to wonder if the emergence from the cocoon,
that is to say, the hatching, really takes place in the order of
primogeniture. Might it not be--by a very singular exception, it
is true, but one which is necessary in such circumstances--that the
youngest of the Osmiae bursts her cocoon first and the oldest last; in
short, that the hatching proceeds from one chamber to the next in the
inverse direction to that which the age of the occupants would lead us
to presume? In that case, the whole difficulty would be removed: each
Osmia, as she rent her silken prison, would find a clear road in front
of her, the Osmiae nearer the outlet having gone out before her. But is
this really how things happen? Our theories very often do not agree with
the insect's practice; even where our reasoning seems most logical,
we should be more prudent to see what happens before venturing on any
positive statements. Leon Dufour was not so prudent when he, the first
in the field, took this little problem in hand. He describes to us the
habits of an Odynerus (Odynerus rubicola, DUF.) who piles up clay cells
in the shaft of a dry bramble-stalk; and, full of enthusiasm for his
industrious Wasp, he goes on to say:

'Picture a string of eight cement shells, placed end to end and closely
wedged inside a wooden sheath. The lowest was undeniably made first and
consequently contains the first-laid egg, which, according to rules,
should give birth to the first winged insect. How do you imagine
that the larva in that first shell was bidden to waive its right of
primogeniture and only to complete its metamorphosis after all its
juniors? What are the conditions brought into play to produce a result
apparently so contrary to the laws of nature? Humble yourself in the
presence of the reality and confess your ignorance, rather than attempt
to hide your embarrassment under vain explanations!

'If the first egg laid by the busy mother were destined to be the
first-born of the Odyneri, that one, in order to see the light
immediately after achieving wings, would have had the option either of
breaking through the double walls of his prison or of perforating, from
bottom to top, the seven shells ahead of him, in order to emerge through
the truncate end of the bramble-stem. Now nature, while refusing any
way of escape laterally, was also bound to veto any direct invasion, the
brutal gimlet-work which would inevitably have sacrificed seven members
of one family for the safety of an only son. Nature is as ingenious in
design as she is fertile in resource, and she must have foreseen and
forestalled every difficulty. She decided that the last-built cradle
should yield the first-born child; that this one should clear the road
for his next oldest brother, the second for the third and so on. And
this is the order in which the birth of our Odyneri of the Brambles
actually takes place.'

Yes, my revered master, I will admit without hesitation that the
bramble-dwellers leave their sheath in the converse order to that of
their ages: the youngest first, the oldest last; if not invariably, at
least very often. But does the hatching, by which I mean the emergence
from the cocoon, take place in the same order? Does the evolution of
the elder wait upon that of the younger, so that each may give those who
would bar his passage time to effect their deliverance and to leave
the road clear? I very much fear that logic has carried your deductions
beyond the bounds of reality. Rationally speaking, my dear sir, nothing
could be more accurate than your inferences; and yet we must forgo
the theory of the strange inversion which you suggest. None of the
Bramble-bees with whom I have experimented behaves after that fashion.
I know nothing personal about Odynerus rubicola, who appears to be a
stranger in my district; but, as the method of leaving must be almost
the same when the habitation is exactly similar, it is enough, I think,
to experiment with some of the bramble-dwellers in order to learn the
history of the rest.

My studies will, by preference, bear upon the Three-pronged Osmia, who
lends herself more readily to laboratory experiments, both because she
is stronger and because the same stalk will contain a goodly number of
her cells. The first fact to be ascertained is the order of hatching.
I take a glass tube, closed at one end, open at the other and of a
diameter similar to that of the Osmia's tunnel. In this I place, one
above the other, exactly in their natural order, the ten cocoons, or
thereabouts, which I extract from a stump of bramble. The operation is
performed in winter. The larvae, at that time, have long been enveloped
in their silken case. To separate the cocoons from one another, I employ
artificial partitions consisting of little round disks of sorghum, or
Indian millet, about half a centimetre thick. (About one-fifth of an
inch.--Translator's Note.) This is a white pith, divested of its fibrous
wrapper and easy for the Osmia's mandibles to attack. My diaphragms are
much thicker than the natural partitions; this is an advantage, as we
shall see. In any case, I could not well use thinner ones, for these
disks must be able to withstand the pressure of the rammer which places
them in position in the tube. On the other hand, the experiment showed
me that the Osmia makes short work of the material when it is a case of
drilling a hole through it.

To keep out the light, which would disturb my insects destined to spend
their larval life in complete darkness, I cover the tube with a thick
paper sheath, easy to remove and replace when the time comes for
observation. Lastly, the tubes thus prepared and containing either
Osmiae or other bramble-dwellers are hung vertically, with the opening
at the top, in a snug corner of my study. Each of these appliances
fulfils the natural conditions pretty satisfactorily: the cocoons from
the same bramble-stick are stacked in the same order which they occupied
in the native shaft, the oldest at the bottom of the tube and the
youngest close to the orifice; they are isolated by means of partitions;
they are placed vertically, head upwards; moreover, my device has
the advantage of substituting for the opaque wall of the bramble a
transparent wall which will enable me to follow the hatching day by day,
at any moment which I think opportune.

The male Osmia splits his cocoon at the end of June and the female at
the beginning of July. When this time comes, we must redouble our watch
and inspect the tubes several times a day if we would obtain exact
statistics of the births. Well, during the six years that I have studied
this question, I have seen and seen again, ad nauseam; and I am in a
position to declare that there is no order governing the sequence of
hatchings, absolutely none. The first cocoon to burst may be the one at
the bottom of the tube, the one at the top, the one in the middle or
in any other part, indifferently. The second to be split may adjoin the
first or it may be removed from it by a number of spaces, either above
or below. Sometimes several hatchings occur on the same day, within the
same hour, some farther back in the row of cells, some farther forward;
and this without any apparent reason for the simultaneity. In short, the
hatchings follow upon one another, I will not say haphazard--for each
of them has its appointed place in time, determined by impenetrable
causes--but at any rate contrary to our calculations, based on this or
the other consideration.

Had we not been deceived by our too shallow logic, we might have
foreseen this result. The eggs are laid in their respective cells at
intervals of a few days, of a few hours. How can this slight difference
in age affect the total evolution, which lasts a year? Mathematical
accuracy has nothing to do with the case. Each germ, each grub has its
individual energy, determined we know not how and varying in each germ
or grub. This excess of vitality belongs to the egg before it leaves the
ovary. Might it not, at the moment of hatching, be the cause why this
or that larva takes precedence of its elders or its juniors, chronology
being altogether a secondary consideration? When the hen sits upon her
eggs, is the oldest always the first to hatch? In the same way, the
oldest larva, lodged in the bottom storey, need not necessarily reach
the perfect state first.

A second argument, had we reflected more deeply on the matter, would
have shaken our faith in any strict mathematical sequence. The same
brood forming the string of cocoons in a bramble-stem contains
both males and females; and the two sexes are divided in the series
indiscriminately. Now it is the rule among the Bees for the males to
issue from the cocoon a little earlier than the females. In the case
of the Three-pronged Osmia, the male has about a week's start.
Consequently, in a populous gallery, there is always a certain number
of males, who are hatched seven or eight days before the females and who
are distributed here and there over the series. This would be enough to
make any regular hatching-sequence impossible in either direction.

These surmises accord with the facts: the chronological sequence of
the cells tells us nothing about the chronological sequence of the
hatchings, which take place without any definite order. There is,
therefore, no surrender of rights of primogeniture, as Leon Dufour
thought: each insect, regardless of the others, bursts its cocoon when
its time comes; and this time is determined by causes which escape our
notice and which, no doubt, depend upon the potentialities of the egg
itself. It is the case with the other bramble-dwellers which I have
subjected to the same test (Osmia detrita, Anthidium scapulare, Solenius
vagus, etc.); and it must also be the case with Odynerus rubicola: so
the most striking analogies inform us. Therefore the singular exception
which made such an impression on Dufour's mind is a sheer logical
illusion.

An error removed is tantamount to a truth gained; and yet, if it were
to end here, the result of my experiment would possess but slight value.
After destruction, let us turn to construction; and perhaps we shall
find the wherewithal to compensate us for an illusion lost. Let us begin
by watching the exit.

The first Osmia to leave her cocoon, no matter what place she occupies
in the series, forthwith attacks the ceiling separating her from the
floor above. She cuts a fairly clean hole in it, shaped like a truncate
cone, having its larger base on the side where the Bee is and its
smaller base opposite. This conformation of the exit-door is a
characteristic of the work. When the insect tries to attack the
diaphragm, it first digs more or less at random; then, as the boring
progresses, the action is concentrated upon an area which narrows
until it presents no more than just the necessary passage. Nor is the
cone-shaped aperture special to the Osmia: I have seen it made by the
other bramble-dwellers through my thick disks of sorghum-pith. Under
natural conditions, the partitions, which, for that matter, are very
thin, are destroyed absolutely, for the contraction of the cell at
the top leaves barely the width which the insect needs. The truncate,
cone-shaped breach has often been of great use to me. Its wide base made
it possible for me, without being present at the work, to judge which
of the two neighbouring Osmiae had pierced the partition; it told me the
direction of a nocturnal migration which I had been unable to witness.

The first-hatched Osmia, wherever she may be, has made a hole in her
ceiling. She is now in the presence of the next cocoon, with her head
at the opening of the hole. In front of her sister's cradle, she usually
stops, consumed with shyness; she draws back into her cell, flounders
among the shreds of the cocoon and the wreckage of the ruined ceiling;
she waits a day, two days, three days, more if necessary. Should
impatience gain the upper hand, she tries to slip between the wall of
the tunnel and the cocoon that blocks the way. She even undertakes the
laborious work of gnawing at the wall, so as to widen the interval, if
possible. We find these attempts, in the shaft of a bramble, at places
where the pith is removed down to the very wood, where the wood itself
is gnawed to some depth. I need hardly say that, although these lateral
inroads are perceptible after the event, they escape the eye at the
moment when they are being made.

If we would witness them, we must slightly modify the glass apparatus.
I line the inside of the tube with a thick piece of whity-brown
packing-paper, but only over one half of the circumference; the other
half is left bare, so that I may watch the Osmia's attempts. Well,
the captive insect fiercely attacks this lining, which to its eyes
represents the pithy layer of its usual abode; it tears it away by tiny
particles and strives to cut itself a road between the cocoon and the
glass wall. The males, who are a little smaller, have a better chance of
success than the females. Flattening themselves, making themselves thin,
slightly spoiling the shape of the cocoon, which, however, thanks to
its elasticity, soon recovers its first condition, they slip through the
narrow passage and reach the next cell. The females, when in a hurry
to get out, do as much, if they find the tube at all amenable to the
process. But no sooner is the first partition passed than a second
presents itself. This is pierced in its turn. In the same way will the
third be pierced and others after that, if the insect can manage them,
as long as its strength holds out. Too weak for these repeated borings,
the males do not go far through my thick plugs. If they contrive to cut
through the first, it is as much as they can do; and, even so, they
are far from always succeeding. But, in the conditions presented by
the native stalk, they have only feeble tissues to overcome; and then,
slipping, as I have said, between the cocoon and the wall, which is
slightly worn owing to the circumstances described, they are able to
pass through the remaining occupied chambers and to reach the outside
first, whatever their original place in the stack of cells. It is just
possible that their early eclosion forces this method of exit upon them,
a method which, though often attempted, does not always succeed. The
females, furnished with stronger tools, make greater progress in my
tubes. I see some who pierce three or four partitions, one after the
other, and are so many stages ahead before those whom they have left
behind are even hatched. While they are engaged in this long and
toilsome operation, others, nearer to the orifice, have cleared a
passage whereof those from a distance will avail themselves. In this
way, it may happen that, when the width of the tube permits, an Osmia in
a back row will nevertheless be one of the first to emerge.

In the bramble-stem, which is of exactly the same diameter as
the cocoon, this escape by the side of the column appears hardly
practicable, except to a few males; and even these have to find a wall
which has so much pith that by removing it they can effect a passage.
Let us then imagine a tube so narrow as to prevent any exit save in the
natural sequence of the cells. What will happen? A very simple thing.
The newly-hatched Osmia, after perforating his partition, finds himself
faced with an unbroken cocoon that obstructs the road. He makes a few
attempts upon the sides and, realizing his impotence, retires into his
cell, where he waits for days and days, until his neighbour bursts her
cocoon in her turn. His patience is inexhaustible. However, it is not
put to an over long test, for within a week, more or less, the whole
string of females is hatched.

When two neighbouring Osmiae are released at the same time, mutual
visits are paid through the aperture between the two rooms: the one
above goes down to the floor below; the one below goes up to the floor
above; sometimes both of them are in the same cell together. Might not
this intercourse tend to cheer them and encourage them to patience?
Meanwhile, slowly, doors are opening here and there through the
separating walls; the road is cleared by sections; and a moment arrives
when the leader of the file walks out. The others follow, if ready; but
there are always laggards who keep the rear-ranks waiting until they are
gone.

To sum up, first, the hatching of the larvae takes place without any
order; secondly, the exodus proceeds regularly from summit to base, but
only in consequence of the insect's inability to move forward so long
as the upper cells are not vacated. We have here not an exceptional
evolution, in the inverse ratio to age, but the simple impossibility of
emerging otherwise. Should a chance occur of going out before its turn,
the insect does not fail to seize it, as we can see by the lateral
movements which send the impatient ones a few ranks ahead and even
release the more favoured altogether. The only remarkable thing that
I perceive is the scrupulous respect shown to the as yet unopened
neighbouring cocoon. However eager to come out, the Osmia is most
careful not to touch it with his mandibles: it is taboo. He will
demolish the partition, he will gnaw the side-wall fiercely, even though
there be nothing left but wood, he will reduce everything around him to
dust; but touch a cocoon that obstructs his way? Never! He will not make
himself an outlet by breaking up his sisters' cradles.

It may happen that the Osmia's patience is in vain and that the
barricade that blocks the way never disappears at all. Sometimes, the
egg in a cell does not mature; and the unconsumed provisions dry up and
become a compact, sticky, mildewed plug, through which the occupants
of the floors below could never clear themselves a passage. Sometimes,
again, a grub dies in its cocoon; and the cradle of the deceased, now
turned into a coffin, forms an everlasting obstacle. How shall the
insect cope with such grave circumstances?

Among the many bramble-stumps which I have collected, some few have
presented a remarkable peculiarity. In addition to the orifice at the
top, they had at the side one and sometimes two round apertures that
looked as though they had been punched out with an instrument. On
opening these stalks, which were old, deserted nests, I discovered the
cause of these very exceptional windows. Above each of them was a cell
full of mouldy honey. The egg had perished and the provisions remained
untouched: hence the impossibility of getting out by the ordinary road.
Walled in by the unsurmountable obstacle, the Osmia on the floor below
had contrived an outlet through the side of the shaft; and those in the
lower storeys had benefited by this ingenious innovation. The usual
door being inaccessible, a side-window had been opened by means of the
insect's jaws. The cocoons, torn, but still in position in the lower
rooms, left no doubt as to this eccentric mode of exit. The same fact,
moreover, was repeated, in several bramble-stumps, in the case of Osmia
tridentata; it was likewise repeated in the case of Anthidium scapulare.
The observation was worth confirming by experiment.

I select a bramble-stem with the thinnest rind possible, so as to
facilitate the Osmiae's work. I split it in half, thus obtaining a
smooth-sided trough which will enable me to judge better of future
exits. The cocoons are next laid out in one of the troughs. I separate
them with disks of sorghum, covering both surfaces of the disk with a
generous layer of sealing-wax, a material which the Osmia's mandibles
are not able to attack. The two troughs are then placed together and
fastened. A little putty does away with the joint and prevents the
least ray of light from penetrating. Lastly, the apparatus is hung up
perpendicularly, with the cocoons' heads up. We have now only to wait.
None of the Osmiae can get out in the usual manner, because each of them
is confined between two partitions coated with sealing-wax. There is but
one resource left to them if they would emerge into the light of day,
that is, for each of them to open a side-window, provided always that
they possess the instinct and the power to do so.

In July, the result is as follows: of twenty Osmiae thus immured, six
succeed in boring a round hole through the wall and making their way
out; the others perish in their cells, without managing to release
themselves. But, when I open the cylinder, when I separate the two
wooden troughs, I realize that all have attempted to escape through the
side, for the wall of each cell bears traces of gnawing concentrated
upon one spot. All, therefore, have acted in the same way as their more
fortunate sisters; they did not succeed, because their strength failed
them. Lastly, in my glass tubes, part-lined with a thick piece of
packing-paper, I often see attempts at making a window in the side of
the cell: the paper is pierced right through with a round hole.

This then is yet another result which I am glad to record in the history
of the bramble-dwellers. When the Osmia, the Anthidium and probably
others are unable to emerge through the customary outlet, they take
an heroic decision and perforate the side of the shaft. It is the last
resource, resolved upon after other methods have been tried in vain. The
brave, the strong succeed; the weak perish in the attempt.

Supposing that all the Osmiae possessed the necessary strength of jaw as
well as the instinct for this sideward boring, it is clear that egress
from each cell through a special window would be much more advantageous
than egress through the common door. The Bee could attend to his release
as soon as he was hatched, instead of postponing it until after the
emancipation of those who come before him; he would thus escape long
waits, which too often prove fatal. In point of fact, it is no uncommon
thing to find bramble-stalks in which several Osmiae have died in their
cells, because the upper storeys were not vacated in time. Yes, there
would be a precious advantage in that lateral opening, which would not
leave each occupant at the mercy of his environment: many die that would
not die. All the Osmiae, when compelled by circumstances, resort to this
supreme method; all have the instinct for lateral boring; but very few
are able to carry the work through. Only the favourites of fate succeed,
those more generously endowed with strength and perseverance.

If the famous law of natural selection, which is said to govern and
transform the world, had any sure foundation; if really the fittest
removed the less fit from the scene; if the future were to the
strongest, to the most industrious, surely the race of Osmiae, which
has been perforating bramble-stumps for ages, should by this time have
allowed its weaker members, who go on obstinately using the common
outlet, to die out and should have replaced them, down to the very last
one, by the stalwart drillers of side-openings. There is an opportunity
here for immense progress; the insect is on the verge of it and is
unable to cross the narrow intervening line. Selection has had ample
time to make its choice; and yet, though there be a few successes, the
failures exceed them in very large measure. The race of the strong has
not abolished the race of the weak: it remains inferior in numbers,
as doubtless it has been since all time. The law of natural selection
impresses me with the vastness of its scope; but, whenever I try to
apply it to actual facts, it leaves me whirling in space, with nothing
to help me to interpret realities. It is magnificent in theory, but it
is a mere gas-bubble in the face of existing conditions. It is majestic,
but sterile. Then where is the answer to the riddle of the world? Who
knows? Who will ever know?

Let us waste no more time in this darkness, which idle theorizing will
not dispel; let us return to facts, humble facts, the only ground that
does not give way under our feet. The Osmia respects her neighbour's
cocoon; and her scruples are so great that, after vainly trying to slip
between that cocoon and the wall, or else to open a lateral outlet, she
lets herself die in her cell rather than effect an egress by forcing
her way through the occupied cells. When the cocoon that blocks the way
contains a dead instead of a live grub, will the result be the same?

In my glass tubes, I let Osmia-cocoons containing a live grub alternate
with Osmia-cocoons in which the grub has been asphyxiated by the fumes
of sulphocarbonic acid. As usual, the storeys are separated by disks of
sorghum. The anchorites, when hatched, do not hesitate long. Once the
partition is pierced, they attack the dead cocoons, go right through
them, reducing the dead grub, now dry and shrivelled, to dust, and at
last emerge, after wrecking everything in their path. The dead cocoons,
therefore, are not spared; they are treated as would be any other
obstacle capable of attack by the mandibles. The Osmia looks upon them
as a mere barricade to be ruthlessly overturned. How is she apprised
that the cocoon, which has undergone no outward change, contains a dead
and not a live grub? It is certainly not by sight. Can it be by sense of
smell? I am always a little suspicious of that sense of smell of
which we do not know the seat and which we introduce on the slightest
provocation as a convenient explanation of that which may transcend our
explanatory powers.

My next test is made with a string of live cocoons. Of course, I cannot
take all these from the same species, for then the experiment would not
differ from the one which we have already witnessed; I take them
from two different species which leave their bramble-stem at separate
periods. Moreover, these cocoons must have nearly the same diameter to
allow of their being stacked in a tube without leaving an empty space
between them and the wall. The two species adopted are Solenius vagus,
which quits the bramble at the end of June, and Osmia detrita, which
comes a little earlier, in the first fortnight of the same month. I
therefore alternate Osmia-cocoons and Solenius-cocoons, with the
latter at the top of the series, either in glass tubes or between two
bramble-troughs joined into a cylinder.

The result of this promiscuity is striking. The Osmiae, which mature
earlier, emerge; and the Solenius-cocoons, as well as their inhabitants,
which by this time have reached the perfect stage, are reduced to
shreds, to dust, wherein it is impossible for me to recognize a vestige,
save perhaps here and there a head, of the exterminated unfortunates.
The Osmia, therefore, has not respected the live cocoons of a foreign
species: she has passed out over the bodies of the intervening Solenii.
Did I say passed over their bodies? She has passed through them,
crunched the laggards between her jaws, treated them as cavalierly as
she treats my disks. And yet those barricades were alive. No matter:
when her hour came, the Osmia went ahead, destroying everything upon
her road. Here, at any rate, is a law on which we can rely: the supreme
indifference of the animal to all that does not form part of itself and
its race.

And what of the sense of smell, distinguishing the dead from the living?
Here, all are alive; and the Bee pierces her way as through a row of
corpses. If I am told that the smell of the Solenii may differ from that
of the Osmiae, I shall reply that such extreme subtlety in the insect's
olfactory apparatus seems to me a rather far-fetched supposition. Then
what is my explanation of the two facts? The explanation? I have none
to give! I am quite content to know that I do not know, which at least
spares me many vain lucubrations. And so I do not know how the Osmia,
in the dense darkness of her tunnel, distinguishes between a live cocoon
and a dead cocoon of the same species; and I know just as little how
she succeeds in recognizing a strange cocoon. Ah, how clearly this
confession of ignorance proves that I am behind the times! I am
deliberately missing a glorious opportunity of stringing big words
together and arriving at nothing.

The bramble-stump is perpendicular, or nearly so; its opening is at the
top. This is the rule under natural conditions. My artifices are able
to alter that state of things; I can place the tube vertically or
horizontally; I can turn its one orifice either up or down; lastly, I
can leave the channel open at both ends, which will give two outlets.
What will happen under these several conditions? That is what we shall
examine with the Three-pronged Osmia.

The tube is hung perpendicularly, but closed at the top and open at the
bottom; in fact, it represents a bramble-stump turned upside down. To
vary and complicate the experiment, the strings of cocoons are arranged
differently in different tubes. In some of them, the heads of the
cocoons are turned downwards, towards the opening; in others, they are
turned upwards, towards the closed end; in others again, the cocoons
alternate in direction, that is to say, they are placed head to head and
rear to rear, turn and turn about. I need not say that the separating
floors are of sorghum.

The result is identical in all these tubes. If the Osmiae have their
heads pointing upwards, they attack the partition above them, as happens
under normal conditions; if their heads point downwards, they turn round
in their cells and set to work as usual. In short, the general outward
trend is towards the top, in whatever position the cocoon be placed.

We here see manifestly at work the influence of gravity, which warns
the insect of its reversed position and makes it turn round, even as it
would warn us if we ourselves happened to be hanging head downwards.
In natural conditions, the insect has but to follow the counsels of
gravity, which tells it to dig upwards, and it will infallibly reach the
exit-door situated at the upper end. But, in my apparatus, these same
counsels betray it: it goes towards the top, where there is no outlet.
Thus misled by my artifices, the Osmiae perish, heaped up on the higher
floors and buried in the ruins.

It nevertheless happens that attempts are made to clear a road
downwards. But it is rare for the work to lead to anything in this
direction, especially in the case of the middle or upper cells. The
insect is little inclined for this progress, the opposite to that to
which it is accustomed; besides, a serious difficulty arises in
the course of this reversed boring. As the Bee flings the excavated
materials behind her, these fall back of their own weight under
her mandibles; the clearance has to be begun anew. Exhausted by her
Sisyphean task, distrustful of this new and unfamiliar method, the Osmia
resigns herself and expires in her cell. I am bound to add, however,
that the Osmiae in the lower storeys, those nearest the exit--sometimes
one, sometimes two or three--do succeed in escaping. In that case, they
unhesitatingly attack the partitions below them, while their companions,
who form the great majority, persist and perish in the upper cells.

It was easy to repeat the experiment without changing anything in the
natural conditions, except the direction of the cocoons: all that I had
to do was to hang up some bramble-stumps as I found them, vertically,
but with the opening downwards. Out of two stalks thus arranged and
peopled with Osmiae, not one of the insects succeeded in emerging. All
the Bees died in the shaft, some turned upwards, others downwards.
On the other hand, three stems occupied by Anthidia discharged their
population safe and sound. The outgoing was effected at the bottom, from
first to last, without the least impediment. Must we take it that
the two sorts of Bees are not equally sensitive to the influences of
gravity? Can the Anthidium, built to pass through the difficult obstacle
of her cotton wallets, be better-adapted than the Osmia to make her way
through the wreckage that keeps falling under the worker's feet; or,
rather, may not this very cotton-waste put a stop to these cataracts of
rubbish which must naturally drive the insect back? This is all quite
possible; but I can say nothing for certain.

Let us now experiment with vertical tubes open at both ends. The
arrangements, save for the upper orifice, are the same as before. The
cocoons, in some of the tubes, have their heads turned down; others,
up; in others again, their positions alternate. The result is similar to
what we have seen above. A few Osmiae, those nearest the bottom orifice,
take the lower road, whatever the direction first occupied by the
cocoon; the others, composing by far the larger number, take the higher
road, even when the cocoon is placed upside down. As both doors are
free, the outgoing is effected at either end with success.

What are we to conclude from all these experiments? First, that gravity
guides the insect towards the top, where the natural door is, and makes
it turn in its cell when the cocoon has been reversed. Secondly, I seem
to suspect an atmospheric influence and, in any case, some second cause
that sends the insect to the outlet. Let us admit that this cause is
the proximity of the outer air acting upon the anchorite through the
partitions.

The animal then is subject, on the one hand, to the promptings of
gravity, and this to an equal degree for all, whatever the storey
inhabited. Gravity is the common guide of the whole series from base to
top. But those in the lower boxes have a second guide, when the bottom
end is open. This is the stimulus of the adjacent air, a more powerful
stimulus than that of gravity. The access of the air from without is
very slight, because of the partitions; while it can be felt in the
nethermost cells, it must decrease rapidly as the storeys ascend.
Wherefore the bottom insects, very few in number, obeying the
preponderant influence, that of the atmosphere, make for the lower
outlet and reverse, if necessary, their original position; those above,
on the contrary, who form the great majority, being guided only by
gravity when the upper end is closed, make for that upper end. It goes
without saying that, if the upper end be open at the same time as the
other, the occupants of the top storeys will have a double incentive to
take the ascending path, though this will not prevent the dwellers on
the lower floors from obeying, by preference, the call of the adjacent
air and adopting the downward road.

I have one means left whereby to judge of the value of my explanation,
namely, to experiment with tubes open at both ends and lying
horizontally. The horizontal position has a twofold advantage. In
the first place, it removes the insect from the influence of gravity,
inasmuch as it leaves it indifferent to the direction to be taken, the
right or the left. In the second place, it does away with the descent
of the rubbish which, falling under the worker's feet when the boring is
done from below, sooner or later discourages her and makes her abandon
her enterprise.

There are a few precautions to be observed for the successful conduct of
the experiment; I recommend them to any one who might care to make the
attempt. It is even advisable to remember them in the case of the tests
which I have already described. The males, those puny creatures, not
built for work, are sorry labourers when confronted with my stout disks.
Most of them perish miserably in their glass cells, without succeeding
in piercing their partitions right through. Moreover, instinct has been
less generous to them than to the females. Their corpses, interspersed
here and there in the series of the cells, are disturbing causes,
which it is wise to eliminate. I therefore choose the larger, more
powerful-looking cocoons. These, except for an occasional unavoidable
error, belong to females. I pack them in tubes, sometimes varying their
position in every way, sometimes giving them all a like arrangement.
It does not matter whether the whole series comes from one and the same
bramble-stump or from several: we are free to choose where we please;
the result will not be altered.

The first time that I prepared one of these horizontal tubes open at
both ends, I was greatly struck by what happened. The series consisted
of ten cocoons. It was divided into two equal batches. The five on the
left went out on the left, the five on the right went out on the right,
reversing, when necessary, their original direction in the cell. It was
very remarkable from the point of view of symmetry; moreover, it was
a very unlikely arrangement among the total number of possible
arrangements, as mathematics will show us.

Let us take n to represent the number of Osmiae. Each of them, once
gravity ceases to interfere and leaves the insect indifferent to either
end of the tube, is capable of two positions, according as she chooses
the exit on the right or on the left. With each of the two positions
of this first Osmia can be combined each of the two positions of the
second, giving us, in all, 2 x 2 = (2 squared) arrangements. Each of
these (2 squared) arrangements can be combined, in its turn, with each
of the two positions of the third Osmia. We thus obtain 2 x 2 x 2 = (2
cubed) arrangements with three Osmiae; and so on, each additional
insect multiplying the previous result by the factor 2. With n Osmiae,
therefore, the total number of arrangements is (2 to the power n.)

But note that these arrangements are symmetrical, two by two: a given
arrangement towards the right corresponds with a similar arrangement
towards the left; and this symmetry implies equality, for, in the
problem in hand, it is a matter of indifference whether a fixed
arrangement correspond with the right or left of the tube. The previous
number, therefore, must be divided by 2. Thus, n Osmiae, according as
each of them turns her head to the right or left in my horizontal tube,
are able to adopt (2 to the power n - 1) arrangements. If n = 10, as in
my first experiment, the number of arrangements becomes (2 to the power
9) = 512.

Consequently, out of 512 ways which my ten insects can adopt for their
outgoing position, there resulted one of those in which the symmetry
was most striking. And observe that this was not an effect obtained by
repeated attempts, by haphazard experiments. Each Osmia in the left half
had bored to the left, without touching the partition on the right; each
Osmia in the right half had bored to the right, without touching
the partition on the left. The shape of the orifices and the surface
condition of the partition showed this, if proof were necessary. There
had been a spontaneous decision, one half in favour of the left, one
half in favour of the right.

The arrangement presents another merit, one superior to that of
symmetry: it has the merit of corresponding with the minimum expenditure
of force. To admit of the exit of the whole series, if the string
consists of n cells, there are originally n partitions to be perforated.
There might even be one more, owing to a complication which I disregard.
There are, I say, at least n partitions to be perforated. Whether each
Osmia pierces her own, or whether the same Osmia pierces several, thus
relieving her neighbours, does not matter to us: the sum-total of the
force expended by the string of Bees will be in proportion to the number
of those partitions, in whatever manner the exit be effected.

But there is another task which we must take seriously into
consideration, because it is often more troublesome than the boring of
the partition: I mean the work of clearing a road through the wreckage.
Let us suppose the partitions pierced and the several chambers blocked
by the resulting rubbish and by that rubbish only, since the horizontal
position precludes any mixing of the contents of different chambers. To
open a passage for itself through these rubbish-heaps, each insect
will have the smallest effort to make if it passes through the smallest
possible number of cells, in short, if it makes for the opening nearest
to it. These smallest individual efforts amount, in the aggregate, to
the smallest total effort. Therefore, by proceeding as they did in my
experiment, the Osmiae effect their exit with the least expenditure of
energy. It is curious to see an insect apply the 'principle of least
action,' so often postulated in mechanics.

An arrangement which satisfies this principle, which conforms to the law
of symmetry and which possesses but one chance in 512, is certainly no
fortuitous result. It is determined by a cause; and, as this cause
acts invariably, the same arrangement must be reproduced if I renew the
experiment. I renewed it, therefore, in the years that followed, with as
many appliances as I could find bramble-stumps; and, at each new test, I
saw once more what I had seen with such interest on the first occasion.
If the number be even--and my column at that time consisted usually
of ten--one half goes out on the right, the other on the left. If the
number be odd--eleven, for instance--the Osmia in the middle goes out
indiscriminately by the right or left exit. As the number of cells to be
traversed is the same on both sides, her expenditure of energy does not
vary with the direction of the exit; and the principle of least action
is still observed.

It was important to discover if the Three-pronged Osmia shared her
capacity, in the first place, with the other bramble-dwellers and, in
the second, with Bees differently housed, but also destined laboriously
to cut a new road for themselves when the hour comes to quit the nest.
Well, apart from a few irregularities, due either to cocoons whose
larva perished in my tubes before developing, or to those inexperienced
workers, the males, the result was the same in the case of Anthidium
scapulare. The insects divided themselves into two equal batches, one
going to the right, the other to the left. Tripoxylon figulus left
me undecided. This feeble insect is not capable of perforating my
partitions; it nibbles at them a little; and I had to judge the
direction from the marks of its mandibles. These marks, which are not
always very plain, do not yet allow me to pronounce an opinion. Solenius
vagus, who is a skilful borer, behaved differently from the Osmia. In a
column of ten, the whole exodus was made in one direction.

On the other hand, I tested the Mason-bee of the Sheds, who, when
emerging under natural conditions, has only to pierce her cement ceiling
and is not confronted with a series of cells. Though a stranger to the
environment which I created for her, she gave me a most positive answer.
Of a column of ten laid in a horizontal tube open at both ends, five
made their way to the right and five to the left. Dioxys cincta, a
parasite in the buildings of both species of Mason-bees, the Chalicodoma
of the Sheds and the Chalicodoma of the Walls (Cf. "The Mason-bees"
by J. Henri Fabre, translated by Alexander Teixeira de Mattos:
passim.--Translator's Note.), provided me with no precise result.
The Leaf-cutting Bee (Megachile apicalis, SPIN. (Cf. Chapter 8 of the
present volume.--Translator's Note.)), who builds her leafy cups in the
old cells of the Chalicodoma of the Walls, acts like the Solenius and
directs her whole column towards the same outlet.

Incomplete as it is, this symmetry shows us how unwise it were to
generalize from the conclusions to which the Three-pronged Osmia leads
us. Whereas some Bees, such as the Anthidium and the Chalicodoma, share
the Osmia's talent for using the twofold exit, others, such as the
Solenius and the Leaf-cutter, behave like a flock of sheep and follow
the first that goes out. The entomological world is not all of a piece;
its gifts are very various: what one is capable of doing another cannot
do; and penetrating indeed would be the eyes that saw the causes of
these differences. Be this as it may, increased research will certainly
show us a larger number of species qualified to use the double outlet.
For the moment, we know three; and that is enough for our purpose.

I will add that, when the horizontal tube has one of its ends closed,
the whole string of Osmiae makes for the open end, turning round to do
so, if need be.

Now that the facts are set forth, let us, if possible, trace the cause.
In a horizontal tube, gravity no longer acts to determine the direction
which the insect will take. Is it to attack the partition on the right
or that on the left? How shall it decide? The more I look into the
matter, the more do my suspicions fall upon the atmospheric influence
which is felt through the two open ends. Of what does this influence
consist? Is it an effect of pressure, of hygrometry, of electrical
conditions, of properties that escape our coarser physical attunement?
He were a bold man who should undertake to decide. Are not we ourselves,
when the weather is about to alter, subject to subtle impressions,
to sensations which we are unable to explain? And yet this vague
sensitiveness to atmospheric changes would not be of much help to us in
circumstances similar to those of my anchorites. Imagine ourselves in
the darkness and the silence of a prison-cell, preceded and followed
by other similar cells. We possess implements wherewith to pierce the
walls; but where are we to strike to reach the final outlet and to reach
it with the least delay? Atmospheric influence would certainly never
guide us.

And yet it guides the insect. Feeble though it be, through the
multiplicity of partitions, it is exercised on one side more than on the
other, because the obstacles are fewer; and the insect, sensible to the
difference between those two uncertainties, unhesitatingly attacks the
partition which is nearer to the open air. Thus is decided the division
of the column into two converse sections, which accomplish the total
liberation with the least aggregate of work. In short, the Osmia and her
rivals 'feel' the free space. This is yet one more sensory faculty which
evolution might well have left us, for our greater advantage. As it has
not done so, are we then really, as many contend, the highest expression
of the progress accomplished, throughout the ages, by the first atom of
glair expanded into a cell?




CHAPTER 2. THE OSMIAE.

February has its sunny days, heralding spring, to which rude winter will
reluctantly yield place. In snug corners, among the rocks, the great
spurge of our district, the characias of the Greeks, the jusclo of the
Provencals, begins to lift its drooping inflorescence and discreetly
opens a few sombre flowers. Here the first Midges of the year will come
to slake their thirst. By the time that the tip of the stalks reaches
the perpendicular, the worst of the cold weather will be over.

Another eager one, the almond-tree, risking the loss of its fruit,
hastens to echo these preludes to the festival of the sun, preludes
which are too often treacherous. A few days of soft skies and it becomes
a glorious dome of white flowers, each twinkling with a roseate eye.
The country, which still lacks green, seems dotted everywhere with
white-satin pavilions. 'Twould be a callous heart indeed that could
resist the magic of this awakening.

The insect nation is represented at these rites by a few of its more
zealous members. There is first of all the Honey-bee, the sworn enemy
of strikes, who profits by the least lull of winter to find out if some
rosemary is not beginning to open somewhere near the hive. The droning
of the busy swarm fills the flowery vault, while a snow of petals falls
softly to the foot of the tree.

Together with the population of harvesters there mingles another, less
numerous, of mere drinkers, whose nesting-time has not yet begun.
This is the colony of the Osmiae, with their copper-coloured skin and
bright-red fleece. Two species have come hurrying up to take part in the
joys of the almond-tree: first, the Horned Osmia, clad in black velvet
on the head and breast and in red velvet on the abdomen; and, a little
later, the Three-horned Osmia, whose livery must be red and red only.
These are the first delegates despatched by the pollen-gleaners to
ascertain the state of the season and attend the festival of the early
blooms. 'Tis but a moment since they burst their cocoon, the winter
abode: they have left their retreats in the crevices of the old walls;
should the north wind blow and set the almond-tree shivering, they will
hasten to return to them. Hail to you, O my dear Osmiae, who yearly,
from the far end of the harmas (The piece of waste ground in which the
author studied his insects in their natural state. Cf. "The Life of
the Fly" by J. Henri Fabre, translated by Alexander Teixeira de Mattos:
chapter 1.--Translator's Note.), opposite snow-capped Ventoux (A
mountain in the Provencal Alps, near Carpentras and Serignan, 6,271
feet.--Translator's Note.), bring me the first tidings of the awakening
of the insect world! I am one of your friends; let us talk about you a
little.

Most of the Osmiae of my region have none of the industry of their
kinswomen of the brambles, that is to say, they do not themselves
prepare the dwelling destined for the laying. They want ready-made
lodgings, such as the old cells and old galleries of Anthophorae and
Chalicodomae. If these favourite haunts are lacking, then a hiding-place
in the wall, a round hole in some bit of wood, the tube of a reed, the
spiral of a dead Snail under a heap of stones are adopted, according to
the tastes of the several species. The retreat selected is divided into
chambers by partition-walls, after which the entrance to the dwelling
receives a massive seal. That is the sum-total of the building done.

For this plasterer's rather than mason's work, the Horned and the
Three-horned Osmia employ soft earth. This material is different from
the Mason-bee's cement, which will withstand wind and weather for many
years on an exposed pebble; it is a sort of dried mud, which turns
to pap on the addition of a drop of water. The Mason-bee gathers her
cementing-dust in the most frequented and driest portions of the road;
she wets it with a saliva which, in drying, gives it the consistency of
stone. The two Osmiae who are the almond-tree's early visitors are
no chemists: they know nothing of the making and mixing of hydraulic
mortar; they limit themselves to gathering natural soaked earth, mud in
short, which they allow to dry without any special preparation on their
part; and so they need deep and well-sheltered retreats, into which the
rain cannot penetrate, or the work would fall to pieces.

While exploiting, in friendly rivalry with the Three-horned Osmia, the
galleries which the Mason-bee of the Sheds good-naturedly surrenders to
both, Latreille's Osmia uses different materials for her partitions and
her doors. She chews the leaves of some mucilaginous plant, some mallow
perhaps, and then prepares a sort of green putty with which she builds
her partitions and finally closes the entrance to the dwelling. When
she settles in the spacious cells of the Masked Anthophora (Anthophora
personata, ILLIG.), the entrance to the gallery, which is wide enough to
admit one's finger, is closed with a voluminous plug of this vegetable
paste. On the earthy banks, hardened by the sun, the home is then
betrayed by the gaudy colour of the lid. It is as though the authorities
had closed the door and affixed to it their great seals of green wax.

So far then as their building-materials are concerned, the Osmiae whom
I have been able to observe are divided into two classes: one building
compartments with mud, the other with a green-tinted vegetable putty.
The first section includes the Horned Osmia and the Three-horned Osmia,
both so remarkable for the horny tubercles on their faces.

The great reed of the south, the Arundo donax, is often used, in the
country, for rough garden-shelters against the mistral or just for
fences. These reeds, the ends of which are chopped off to make them all
the same length, are planted perpendicularly in the earth. I have often
explored them in the hope of finding Osmia-nests. My search has very
seldom succeeded. The failure is easily explained. The partitions and
the closing-plug of the Horned and of the Three-horned Osmia are made,
as we have seen, of a sort of mud which water instantly reduces to pap.
With the upright position of the reeds, the stopper of the opening would
receive the rain and would become diluted; the ceilings of the storeys
would fall in and the family would perish by drowning. Therefore the
Osmia, who knew of these drawbacks before I did, refuses the reeds when
they are placed perpendicularly.

The same reed is used for a second purpose. We make canisses of it,
that is to say, hurdles, which, in spring, serve for the rearing of
silk-worms and, in autumn, for the drying of figs. At the end of April
and during May, which is the time when the Osmiae work, the canisses
are indoors, in the silk-worm nurseries, where the Bee cannot take
possession of them; in autumn, they are outside, exposing their layers
of figs and peeled peaches to the sun; but by that time the Osmiae have
long disappeared. If, however, during the spring, an old, disused hurdle
is left out of doors, in a horizontal position, the Three-horned Osmia
often takes possession of it and makes use of the two ends, where the
reeds lie truncated and open.

There are other quarters that suit the Three-horned Osmia, who is not
particular, it seems to me, and will make shift with any hiding-place,
so long as it has the requisite conditions of diameter, solidity,
sanitation and kindly darkness. The most original dwellings that I know
her to occupy are disused Snail-shells, especially the house of the
Common Snail (Helix aspersa). Let us go to the slope of the hills thick
with olive-trees and inspect the little supporting-walls which are
built of dry stones and face the south. In the crevices of this insecure
masonry, we shall reap a harvest of old Snail-shells, plugged with earth
right up to the orifice. The family of the Three-horned Osmia is settled
in the spiral of those shells, which is subdivided into chambers by mud
partitions.

Let us inspect the stone-heaps, especially those which come from the
quarry-works. Here we often find the Field-mouse sitting on a grass
mattress, nibbling acorns, almonds, olive-stones and apricot-stones. The
Rodent varies his diet: to oily and farinaceous foods he adds the Snail.
When he is gone, he has left behind him, under the overhanging stones,
mixed up with the remains of other victuals, an assortment of empty
shells, sometimes plentiful enough to remind me of the heap of Snails
which, cooked with spinach and eaten country-fashion on Christmas Eve,
are flung away next day by the housewife. This gives the Three-horned
Osmia a handsome collection of tenements; and she does not fail to
profit by them. Then again, even if the Field-mouse's conchological
museum be lacking, the same broken stones serve as a refuge for
Garden-snails who come to live there and end by dying there. When we see
Three-horned Osmiae enter the crevices of old walls and of stone-heaps,
there is no doubt about their occupation: they are getting free lodgings
out of the old Snail-shells of those labyrinths.

The Horned Osmia, who is less common, might easily also be less
ingenious, that is to say, less rich in varieties of houses. She seems
to scorn empty shells. The only homes that I know her to inhabit are the
reeds of the hurdles and the deserted cells of the Masked Anthophora.

All the other Osmiae whose method of nest-building I know work with
green putty, a paste made of some crushed leaf or other; and none of
them, except Latreille's Osmia, is provided with the horned or tubercled
armour of the mud-kneaders. I should like to know what plants are used
in making the putty; probably each species has its own preferences and
its little professional secrets; but hitherto observation has taught me
nothing concerning these details. Whatever worker prepare it, the putty
is very much the same in appearance. When fresh, it is always a clear
dark green. Later, especially in the parts exposed to the air, it
changes, no doubt through fermentation, to the colour of dead leaves,
to brown, to dull-yellow; and the leafy character of its origin is no
longer apparent. But uniformity in the materials employed must not
lead us to believe in uniformity in the lodging; on the contrary, this
lodging varies greatly with the different species, though there is a
marked predilection in favour of empty shells. Thus Latreille's Osmia,
together with the Three-horned Osmia, uses the spacious structures
of the Mason-bee of the Sheds; she likes the magnificent cells of the
Masked Anthophora; and she is always ready to establish herself in the
cylinder of any reed lying flat on the ground.

I have already spoken of an Osmia (O. cyanoxantha, PEREZ) who elects
to make her home in the old nests of the Mason-bee of the Pebbles. (Cf.
"The Mason-bees": chapter 10.--Translator's Note.) Her closing-plug is
made of a stout concrete, consisting of fair-sized bits of gravel
sunk in the green paste; but for the inner partitions she employs
only unalloyed putty. As the outer door, situated on the curve of an
unprotected dome, is exposed to the inclemencies of the weather,
the mother has to think of fortifying it. Danger, no doubt, is the
originator of that gritty concrete.

The Golden Osmia (O. aurulenta, LATR.) absolutely insists on an empty
Snail-shell as her residence. The Brown or Girdled Snail, the Garden
Snail and especially the Common Snail, who has a more spacious spiral,
all scattered at random in the grass, at the foot of the walls and of
the sun-swept rocks, furnish her with her usual dwelling-house. Her
dried putty is a kind of felt full of short white hairs. It must come
from some hairy-leaved plant, one of the Boragineae perhaps, rich both
in mucilage and the necessary bristles.

The Red Osmia (O. rufo-hirta, LATR.) has a weakness for the Brown Snail
and the Garden Snail, in whose shells I find her taking refuge in April
when the north-wind blows. I am not yet much acquainted with her work,
which should resemble that of the Golden Osmia.

The Green Osmia (O. viridana, MORAWITZ) takes up her quarters, tiny
creature that she is, in the spiral staircase of Bulimulus radiatus. It
is a very elegant, but very small lodging, to say nothing of the fact
that a considerable portion is taken up with the green-putty plug. There
is just room for two.

The Andrenoid Osmia (O. andrenoides, LATR.), who looks so curious, with
her naked red abdomen, appears to build her nest in the shell of the
Common Snail, where I discover her refuged.

The Variegated Osmia (O. versicolor, LATR.) settles in the Garden
Snail's shell, almost right at the bottom of the spiral.

The Blue Osmia (O. cyanea, KIRB.) seems to me to accept many different
quarters. I have extracted her from old nests of the Mason-bee of the
Pebbles, from the galleries dug in a roadside bank by the Colletes (A
short-tongued Burrowing-bee known also as the Melitta.--Translator's
Note.) and lastly from the cavities made by some digger or other in the
decayed trunk of a willow-tree.

Morawitz' Osmia (O. Morawitzi, PEREZ) is not uncommon in the old nests
of the Mason-bee of the Pebbles, but I suspect her of favouring other
lodgings besides.

The Three-pronged Osmia (O. tridentata, DUF. and PER.) creates a home of
her own, digging herself a channel with her mandibles in dry bramble and
sometimes in danewort. It mixes a few scrapings of perforated pith with
the green paste. Its habits are shared by the Ragged Osmia (O. detrita,
PEREZ) and by the Tiny Osmia (O. parvula, DUF.)

The Chalicodoma works in broad daylight, on a tile, on a pebble, on a
branch in the hedge; none of her trade-practises is kept a secret from
the observer's curiosity. The Osmia loves mystery. She wants a dark
retreat, hidden from the eye. I would like, nevertheless, to watch
her in the privacy of her home and to witness her work with the same
facility as if she were nest-building in the open air. Perhaps there are
some interesting characteristics to be picked up in the depths of her
retreats. It remains to be seen whether my wish can be realized.

When studying the insect's mental capacity, especially its very
retentive memory for places, I was led to ask myself whether it would
not be possible to make a suitably-chosen Bee build in any place that I
wished, even in my study. And I wanted, for an experiment of this sort,
not an individual but a numerous colony. My preference leant towards the
Three-horned Osmia, who is very plentiful in my neighbourhood, where,
together with Latreille's Osmia, she frequents in particular the
monstrous nests of the Chalicodoma of the Sheds. I therefore thought
out a scheme for making the Three-horned Osmia accept my study as her
settlement and build her nests in glass tubes, through which I could
easily watch the progress. To these crystal galleries, which might well
inspire a certain distrust, were to be added more natural retreats:
reeds of every length and thickness and disused Chalicodoma-cells taken
from among the biggest and the smallest. A scheme like this sounds mad.
I admit it, while mentioning that perhaps none ever succeeded so well
with me. We shall see as much presently.

My method is extremely simple. All I ask is that the birth of my
insects, that is to say, their first seeing the light, their emerging
from the cocoon, should take place on the spot where I propose to make
them settle. Here there must be retreats of no matter what nature,
but of a shape similar to that in which the Osmia delights. The first
impressions of sight, which are the most long-lived of any, shall bring
back my insects to the place of their birth. And not only will the
Osmiae return, through the always open windows, but they will always
nidify on the natal spot if they find something like the necessary
conditions.

And so, all through the winter, I collect Osmia-cocoons, picked up in
the nests of the Mason-bee of the Sheds; I go to Carpentras to glean a
more plentiful supply in the nests of the Hairy-footed Anthophora, that
old acquaintance whose wonderful cities I used to undermine when I
was studying the history of the Oil-beetles. (This study is not yet
translated into English; but cf. "The Life of the Fly": chapters 2
and 4.--Translator's Note.) Later, at my request, a pupil and intimate
friend of mine, M. Henri Devillario, president of the civil court at
Carpentras, sends me a case of fragments broken off the banks frequented
by the Hairy-footed Anthophora and the Anthophora of the Walls, useful
clods which furnish a handsome adjunct to my collection. Indeed, at the
end, I find myself with handfuls of cocoons of the Three-horned Osmia.
To count them would weary my patience without serving any particular
purpose.

I spread out my stock in a large open box on a table which receives
a bright diffused light but not the direct rays of the sun. The table
stands between two windows facing south and overlooking the garden. When
the moment of hatching comes, those two windows will always remain open
to give the swarm entire liberty to go in and out as it pleases.
The glass tubes and the reed-stumps are laid here and there, in fine
disorder, close to the heap of cocoons and all in a horizontal position,
for the Osmia will have nothing to do with upright reeds. The hatching
of some of the Osmiae will therefore take place under cover of the
galleries destined to be the building-yard later; and the site will be
all the more deeply impressed on their memory. When I have made these
comprehensive arrangements, there is nothing more to be done; and I wait
patiently for the building-season to open.

My Osmiae leave their cocoons in the second half of April. Under the
immediate rays of the sun, in well-sheltered nooks, the hatching would
occur a month earlier, as we can see from the mixed population of
the snowy almond-tree. The constant shade in my study has delayed the
awakening, without, however, making any change in the nesting-period,
which synchronizes with the flowering of the thyme. We now have, around
my working-table, my books, my jars and my various appliances, a buzzing
crowd that goes in and out of the windows at every moment. I enjoin the
household henceforth not to touch a thing in the insects' laboratory, to
do no more sweeping, no more dusting. They might disturb the swarm and
make it think that my hospitality was not to be trusted. I suspect that
the maid, wounded in her self-esteem at seeing so much dust accumulating
in the master's study, did not always respect my prohibitions and came
in stealthily, now and again, to give a little sweep of the broom.
At any rate, I came across a number of Osmiae who seemed to have been
crushed under foot while taking a sunbath on the floor in front of the
window. Perhaps it was I myself who committed the misdeed in a heedless
moment. There is no great harm done, for the population is a numerous
one; and, notwithstanding those crushed by inadvertence, notwithstanding
the parasites wherewith many of the cocoons are infested,
notwithstanding those who may have come to grief outside or been unable
to find their way back, notwithstanding the deduction of one-half which
we must make for the males: notwithstanding all this, during four or
five weeks I witness the work of a number of Osmiae which is much too
large to allow of my watching their individual operations. I content
myself with a few, whom I mark with different-coloured spots to
distinguish them; and I take no notice of the others, whose finished
work will have my attention later.

The first to appear are the males. If the sun is bright, they flutter
around the heap of tubes as if to take careful note of the locality;
blows are exchanged and the rival swains indulge in mild skirmishing
on the floor, then shake the dust off their wings and fly away. I find
them, opposite my window, in the refreshment-bar of the lilac-bush,
whose branches bend with the weight of their scented panicles. Here the
Bees get drunk with sunshine and draughts of honey. Those who have had
their fill come home and fly assiduously from tube to tube, placing
their heads in the orifices to see if some female will at last make up
her mind to emerge.

One does, in point of fact. She is covered with dust and has the
disordered toilet that is inseparable from the hard work of the
deliverance. A lover has seen her, so has a second, likewise a third.
All crowd round her. The lady responds to their advances by clashing her
mandibles, which open and shut rapidly, several times in succession. The
suitors forthwith fall back; and they also, no doubt to keep up their
dignity, execute savage mandibular grimaces. Then the beauty retires
into the arbour and her wooers resume their places on the threshold. A
fresh appearance of the female, who repeats the play with her jaws; a
fresh retreat of the males, who do the best they can to flourish their
own pincers. The Osmiae have a strange way of declaring their passion:
with that fearsome gnashing of their mandibles, the lovers look as
though they meant to devour each other. It suggests the thumps affected
by our yokels in their moments of gallantry.

The ingenious idyll is soon over. By turns greeting and greeted with a
clash of jaws, the female leaves her gallery and begins impassively to
polish her wings. The rivals rush forward, hoist themselves on top of
one another and form a pyramid of which each struggles to occupy the
base by toppling over the favoured lover. He, however, is careful not
to let go; he waits for the strife overhead to calm down; and, when the
supernumeraries realize that they are wasting their time and throw up
the game, the couple fly away far from the turbulent rivals. This is all
that I have been able to gather about the Osmia's nuptials.

The females, who grow more numerous from day to day, inspect the
premises; they buzz outside the glass galleries and the reed dwellings;
they go in, stay for a while, come out, go in again and then fly away
briskly into the garden. They return, first one, then another. They halt
outside, in the sun, on the shutters fastened back against the wall;
they hover in the window-recess, come inside, go to the reeds and give a
glance at them, only to set off again and to return soon after. Thus
do they learn to know their home, thus do they fix their birthplace in
their memory. The village of our childhood is always a cherished spot,
never to be effaced from our recollection. The Osmia's life endures
for a month; and she acquires a lasting remembrance of her hamlet in
a couple of days. 'Twas there that she was born; 'twas there that she
loved; 'tis there that she will return. Dulces reminiscitur Argos. ('Now
falling by another's wound, his eyes He casts to heaven, on Argos thinks
and dies.'--"Aeneid," Book 10 Dryden's translation.)

At last each has made her choice. The work of construction begins; and
my expectations are fulfilled far beyond my wishes. The Osmiae build
nests in all the retreats which I have placed at their disposal. The
glass tubes, which I cover with a sheet of paper to produce the shade
and mystery favourable to concentrated toil, do wonderfully well. All,
from first to last, are occupied. The Osmiae quarrel for the possession
of these crystal palaces, hitherto unknown to their race. The reeds
and the paper tubes likewise do wonderfully. The number provided is
too small; and I hasten to increase it. Snail-shells are recognized as
excellent abodes, though deprived of the shelter of the stone-heap; old
Chalicodoma-nests, down to those of the Chalicodoma of the Shrubs (Cf.
"The Mason-bees": chapters 4 and 10.--Translator's Note.), whose cells
are so small, are eagerly occupied. The late-comers, finding nothing
else free, go and settle in the locks of my table-drawers. There are
daring ones who make their way into half-open boxes containing ends of
glass tubes in which I have stored my most recent acquisitions: grubs,
pupae and cocoons of all kinds, whose evolution I wished to study.
Whenever these receptacles have an atom of free space, they claim the
right to build there, whereas I formally oppose the claim. I hardly
reckoned on such a success, which obliges me to put some order into
the invasion with which I am threatened. I seal up the locks, I shut my
boxes, I close my various receptacles for old nests, in short I remove
from the building-yard any retreat of which I do not approve. And now, O
my Osmiae, I leave you a free field!

The work begins with a thorough spring-cleaning of the home. Remnants
of cocoons, dirt consisting of spoilt honey, bits of plaster from broken
partitions, remains of dried Mollusc at the bottom of a shell: these and
much other insanitary refuse must first of all disappear. Violently the
Osmia tugs at the offending object and tears it out; and then off she
goes, in a desperate hurry, to dispose of it far away from the study.
They are all alike, these ardent sweepers: in their excessive zeal, they
fear lest they should block up the place with a speck of dust which they
might drop in front of the new house. The glass tubes, which I myself
have rinsed under the tap, are not exempt from a scrupulous cleaning.
The Osmia dusts them, brushes them thoroughly with her tarsi and then
sweeps them out backwards. What does she pick up? Not a thing. It makes
no difference: as a conscientious housewife, she gives the place a touch
of the broom nevertheless.

Now for the provisions and the partition-walls. Here the order of the
work changes according to the diameter of the cylinder. My glass tubes
vary greatly in dimensions. The largest have an inner width of a dozen
millimetres (Nearly half an inch.--Translator's Note.); the narrowest
measure six or seven. (About a quarter of an inch.--Translator's Note.)
In the latter, if the bottom suit her, the Osmia sets to work bringing
pollen and honey. If the bottom do not suit her, if the sorghum-pith
plug with which I have closed the rear-end of the tube be too irregular
and badly-joined, the Bee coats it with a little mortar. When this small
repair is made, the harvesting begins.

In the wider tubes, the work proceeds quite differently. At the moment
when the Osmia disgorges her honey and especially at the moment when,
with her hind-tarsi, she rubs the pollen-dust from her ventral brush,
she needs a narrow aperture, just big enough to allow of her passage.
I imagine that, in a straitened gallery, the rubbing of her whole body
against the sides gives the harvester a support for her brushing-work.
In a spacious cylinder, this support fails her; and the Osmia starts
with creating one for herself, which she does by narrowing the channel.
Whether it be to facilitate the storing of the victuals or for any other
reason, the fact remains that the Osmia housed in a wide tube begins
with the partitioning.

Her division is made by a dab of clay placed at right angles to the
axis of the cylinder, at a distance from the bottom determined by the
ordinary length of a cell. This wad is not a complete round; it is more
crescent-shaped, leaving a circular space between it and one side of the
tube. Fresh layers are swiftly added to the dab of clay; and soon the
tube is divided by a partition which has a circular opening at the side
of it, a sort of dog-hole through which the Osmia will proceed to knead
the Bee-bread. When the victualling is finished and the egg laid upon
the heap, the hole is closed and the filled-up partition becomes the
bottom of the next cell. Then the same method is repeated, that is to
say, in front of the just completed ceiling a second partition is built,
again with a side-passage, which is stouter, owing to its distance from
the centre, and better able to withstand the numerous comings and goings
of the housewife than a central orifice, deprived of the direct support
of the wall, could hope to be. When this partition is ready, the
provisioning of the second cell is effected; and so on until the wide
cylinder is completely stocked.

The building of this preliminary party-wall, with a narrow, round
dog-hole, for a chamber to which the victuals will not be brought until
later is not restricted to the Three-horned Osmia; it is also frequently
found in the case of the Horned Osmia and of Latreille's Osmia. Nothing
could be prettier than the work of the last-named, who goes to the
plants for her material and fashions a delicate sheet in which she cuts
a graceful arch. The Chinaman partitions his house with paper screens;
Latreille's Osmia divides hers with disks of thin green cardboard
perforated with a serving-hatch which remains until the room is
completely furnished. When we have no glass houses at our disposal,
we can see these little architectural refinements in the reeds of the
hurdles, if we open them at the right season.

By splitting the bramble-stumps in the course of July, we perceive
also that the Three-pronged Osmia, notwithstanding her narrow gallery,
follows the same practice as Latreille's Osmia, with a difference. She
does not build a party-wall, which the diameter of the cylinder would
not permit; she confines herself to putting up a frail circular pad of
green putty, as though to limit, before any attempt at harvesting,
the space to be occupied by the Bee-bread, whose depth could not be
calculated afterwards if the insect did not first mark out its confines.
Can there really be an act of measuring? That would be superlatively
clever. Let us consult the Three-horned Osmia in her glass tubes.

The Osmia is working at her big partition, with her body outside the
cell which she is preparing. From time to time, with a pellet of mortar
in her mandibles, she goes in and touches the previous ceiling with
her forehead, while the tip of her abdomen quivers and feels the pad in
course of construction. One might well say that she is using the length
of her body as a measure, in order to fix the next ceiling at the
proper distance. Then she resumes her work. Perhaps the measure was
not correctly taken; perhaps her memory, a few seconds old, has already
become muddled. The Bee once more ceases laying her plaster and again
goes and touches the front wall with her forehead and the back wall with
the tip of her abdomen. Looking at that body trembling with eagerness,
extended to its full length to touch the two ends of the room, how can
we fail to grasp the architect's grave problem? The Osmia is measuring;
and her measure is her body. Has she quite done, this time? Oh dear
no! Ten times, twenty times, at every moment, for the least particle of
mortar which she lays, she repeats her mensuration, never being quite
certain that her trowel is going just where it should.

Meanwhile, amid these frequent interruptions, the work progresses and
the partition gains in width. The worker is bent into a hook, with her
mandibles on the inner surface of the wall and the tip of her abdomen
on the outer surface. The soft masonry stands between the two points of
purchase. The insect thus forms a sort of rolling-press, in which the
mud wall is flattened and shaped. The mandibles tap and furnish mortar;
the end of the abdomen also pats and gives brisk trowel-touches. This
anal extremity is a builder's tool; I see it facing the mandibles on
the other side of the partition, kneading and smoothing it all over,
flattening the little lump of clay. It is a singular implement, which
I should never have expected to see used for this purpose. It takes an
insect to conceive such an original idea, to do mason's work with its
behind! During this curious performance, the only function of the legs
is to keep the worker steady by spreading out and clinging to the walls
of the tunnel.

The partition with the hole in it is finished. Let us go back to the
measuring of which the Osmia was so lavish. What a magnificent argument
in favour of the reasoning-power of animals! To find geometry, the
surveyor's art, in an Osmia's tiny brain! An insect that begins by
taking the measurements of the room to be constructed, just as any
master-builder might do! Why, it's splendid, it's enough to cover with
confusion those horrible sceptics who persist in refusing to admit the
animal's 'continuous little flashes of atoms of reason!'

O common-sense, veil your face! It is with this gibberish about
continuous flashes of atoms of reason that men pretend to build up
science to-day! Very well, my masters; the magnificent argument with
which I am supplying you lacks but one little detail, the merest trifle:
truth! Not that I have not seen and plainly seen all that I am relating;
but measuring has nothing to do with the case. And I can prove it by
facts.

If, in order to see the Osmia's nest as a whole, we split a reed
lengthwise, taking care not to disturb its contents; or, better still,
if we select for examination the string of cells built in a glass tube,
we are forthwith struck by one detail, namely, the uneven distances
between the partitions, which are placed almost at right angles to the
axis of the cylinder. It is these distances which fix the size of
the chambers, which, with a similar base, have different heights and
consequently unequal holding-capacities. The bottom partitions, the
oldest, are farther apart; those of the front part, near the orifice,
are closer together. Moreover, the provisions are plentiful in the
loftier cells, whereas they are niggardly and reduced to one-half or
even one-third in the cells of lesser height.

Here are a few examples of these inequalities. A glass tube with a
diameter of 12 millimetres (.468 inch.--Translator's Note.), inside
measurement, contains ten cells. The five lower ones, beginning with the
bottom-most, have as the respective distances between their partitions,
in millimetres:

11, 12, 16, 13, 11. (.429,.468,.624,.507,.429 inch.--Translator's Note.)

The five upper ones measure between their partitions:

7, 7, 5, 6, 7. (.273,.273,.195,.234,.273 inch.--Translator's Note.)

A reed-stump 11 millimetres (.429 inch.--Translator's Note.) across the
inside contains fifteen cells; and the respective distances between the
partitions of those cells, starting from the bottom, are:

13, 12, 12, 9, 9, 11, 8, 8, 7, 7, 7, 6, 6, 6, 7. (.507,.468,.468,
.351,.351,.429,.312,.312,.273,.273,.273,.234,.234,.234, .273
inch.--Translator's Note.)

When the diameter of the tunnel is less, the partitions can be still
further apart, though they retain the general characteristic of being
closer to one another the nearer they are to the orifice. A reed of five
millimetres (.195 inch.--Translator's Note.) in diameter, gives me the
following distances, always starting from the bottom:

22, 22, 20, 20, 12, 14. (.858,.858,.78,.78,.468,.546 inch.--Translator's
Note.)

Another, of 9 millimetres (.351 inch.--Translator's Note.), gives me:

15, 14, 11, 10, 10, 9, 10. (.585,.546,.429,.39,.39,.351,.39
inch.--Translator's Note.)

A glass tube of 8 millimetres (.312 inch.--Translator's Note.) yields:

15, 14, 20, 10, 10, 10. (.585,.546,.78,.39,.39,.39 inch.--Translator's
Note.).

I could fill pages and pages with such figures, if I cared to print all
my notes. Do they prove that the Osmia is a geometrician, employing a
strict measure based on the length of her body? Certainly not, because
many of those figures exceed the length of the insect; because sometimes
a higher number follows suddenly upon a lower; because the same string
contains a figure of one value and another figure of but half that
value. They prove only one thing: the marked tendency of the insect to
shorten the distance between the party-walls as the work proceeds. We
shall see later that the large cells are destined for the females and
the small ones for the males.

Is there not at least a measuring adapted to each sex? Again, not so;
for in the first series, where the females are housed, instead of the
interval of 11 millimetres, which occurs at the beginning and the end,
we find, in the middle of the series, an interval of 16 millimetres,
while in the second series, reserved for the males, instead of the
interval of 7 millimetres at the beginning and the end, we have an
interval of 5 millimetres in the middle. It is the same with the other
series, each of which shows a striking discrepancy in its figures. If
the Osmia really studied the dimensions of her chambers and measured
them with the compasses of her body, how could she, with her delicate
mechanism, fail to notice mistakes of 5 millimetres, almost half her own
length?

Besides, all idea of geometry vanishes if we consider the work in a tube
of moderate width. Here, the Osmia does not fix the front partition in
advance; she does not even lay its foundation. Without any boundary-pad,
with no guiding mark for the capacity of the cell, she busies herself
straightway with the provisioning. When the heap of Bee-bread is judged
sufficient, that is, I imagine, when her tired body tells her that she
has done enough harvesting, she closes up the chamber. In this case,
there is no measuring; and yet the capacity of the cell and the quantity
of the victuals fulfil the regular requirements of one or the other sex.

Then what does the Osmia do when she repeatedly stops to touch the
front partition with her forehead and the back partition, the one in the
course of building, with the tip of her abdomen? I have no idea what
she does or what she has in view. I leave the interpretation of this
performance to others, more venturesome than I. Plenty of theories are
based on equally shaky foundations. Blow on them and they sink into the
quagmire of oblivion.

The laying is finished, or perhaps the cylinder is full. A final
partition closes the last cell. A rampart is now built, at the orifice
of the tube itself, to forbid the ill-disposed all access to the home.
This is a thick plug, a massy work of fortification, whereon the Osmia
spends enough mortar to partition off any number of cells. A whole day
is not too long for making this barricade, especially in view of the
minute finishing-touches, when the Osmia fills up with putty every chink
through which the least atom could slip. The mason completing a wall
smooths his plaster and brings it to a fine surface while it is still
wet; the Osmia does the same, or almost. With little taps of the
mandibles and a continual shaking of her head, a sign of her zest for
the work, she smooths and polishes the surface of the lid for hours at a
time. After such pains, what foe could visit the dwelling?

And yet there is one, an Anthrax, A. sinuata (Cf. "The Life of the Fly":
chapters 2 and 4.--Translator's Note.), who will come later on, in the
height of summer, and succeed, invisible bit of thread that she is, in
making her way to the grub through the thickness of the door and the web
of the cocoon. In many cells, mischief of another kind has already been
done. During the progress of the works, an impudent Midge, one of the
Tachina-flies, who feeds her family on the victuals amassed by the Bee,
hovers in front of the galleries. Does she penetrate to the cells and
lay her eggs there in the mother's absence? I could never catch the
sneak in the act. Does she, like that other Tachina who ravages cells
stocked with game (The cells of the Hunting Wasps.--Translator's Note.),
nimbly deposit her eggs on the Osmia's harvest at the moment when the
Bee is going indoors? It is possible, though I cannot say for certain.
The fact remains that we soon see the Midge's grub-worms swarming around
the larva, the daughter of the house. There are ten, fifteen, twenty or
more of them gnawing with their pointed mouths at the common dish and
turning the food into a heap of fine, orange-coloured vermicelli. The
Bee's grub dies of starvation. It is life, life in all its ferocity
even in these tiny creatures. What an expenditure of ardent labour, of
delicate cares, of wise precautions, to arrive at...what? Her offspring
sucked and drained dry by the hateful Anthrax; her family sweated and
starved by the infernal Tachina.

The victuals consist mostly of yellow flour. In the centre of the heap,
a little honey is disgorged, which turns the pollen-dust into a firm,
reddish paste. On this paste the egg is laid, not flat, but upright,
with the fore-end free and the hind-end lightly held and fixed in the
plastic mass. When hatched, the young grub, kept in its place by its
rear-end, need only bend its neck a little to find the honey-soaked
paste under its mouth. When it grows stronger, it will release itself
from its support and eat up the surrounding flour.

All this is touching, in its maternal logic. For the new-born, dainty
bread-and-honey; for the adolescent, dry bread. In cases where
the provisions are all of a kind, these delicate precautions are
superfluous. The victuals of the Anthophorae and the Chalicodomae
consist of flowing honey, the same throughout. The egg is then laid at
full length on the surface, without any particular arrangement, thus
compelling the new-born grub to take its first mouthfuls at random. This
has no drawback, as the food is of the same quality throughout. But,
with the Osmia's provisions--dry powder on the edges, jam in the
centre--the grub would be in danger if its first meal were not regulated
in advance. To begin with pollen not seasoned with honey would be
fatal to its stomach. Having no choice of its mouthfuls because of its
immobility and being obliged to feed on the spot where it was hatched,
the young grub must needs be born on the central mass, where it has only
to bend its head a little way in order to find what its delicate stomach
calls for. The place of the egg, therefore, fixed upright by its base in
the middle of the red jam, is most judiciously chosen. What a contrast
between this exquisite maternal forethought and the horrible destruction
by the Anthrax and the Midge!

The egg is rather large for the size of the Osmia. It is cylindrical,
slightly curved, rounded at both ends and transparent. It soon becomes
cloudy, while remaining diaphanous at each extremity. Fine lines, hardly
perceptible to the most penetrating lens, show themselves in transverse
circles. These are the first signs of segmentation. A contraction
appears in the front hyaline part, marking the head. An extremely
thin opaque thread runs down either side. This is the cord of tracheae
communicating between one breathing-hole and another. At last, the
segments show distinctly, with their lateral pads. The grub is born.

At first, one would think that there was no hatching in the proper sense
of the word--that is to say, no bursting and casting of a wrapper.
The most minute attention is necessary to show that appearances are
deceptive and that actually a fine membrane is thrown off from front to
back. This infinitesimal shred is the shell of the egg.

The grub is born. Fixed by its base, it curves into an arc and bends its
head, until now held erect, down to the red mass. The meal begins. Soon
a yellow cord occupying the front two-thirds of the body proclaims that
the digestive apparatus is swelling out with food. For a fortnight,
consume your provender in peace, my child; then spin your cocoon: you
are now safe from the Tachina! Shall you be safe from the Anthrax'
sucker later on? Alack!




CHAPTER 3. THE DISTRIBUTION OF THE SEXES.

Does the insect know beforehand the sex of the egg which it is about to
lay? When examining the stock of food in the cells just now, we began
to suspect that it does, for each little heap of provisions is carefully
proportioned to the needs at one time of a male and at another of a
female. What we have to do is to turn this suspicion into a certainty
demonstrated by experiment. And first let us find out how the sexes are
arranged.

It is not possible to ascertain the chronological order of a laying,
except by going to suitably-chosen species. Digging up the burrows of
Cerceris-, Bembex- or Philanthus-wasps will never tell us that this grub
has taken precedence of that in point of time nor enable us to decide
whether one cocoon in a colony belongs to the same family as another. To
compile a register of births is absolutely impossible here. Fortunately
there are a few species in which we do not find this difficulty: these
are the Bees who keep to one gallery and build their cells in storeys.
Among the number are the different inhabitants of the bramble-stumps,
notably the Three-pronged Osmiae, who form an excellent subject for
observation, partly because they are of imposing-size--bigger than any
other bramble-dwellers in my neighbourhood--partly because they are so
plentiful.

Let us briefly recall the Osmia's habits. Amid the tangle of a hedge, a
bramble-stalk is selected, still standing, but a mere withered stump. In
this the insect digs a more or less deep tunnel, an easy piece of work
owing to the abundance of soft pith. Provisions are heaped up right at
the bottom of the tunnel and an egg is laid on the surface of the
food: that is the first-born of the family. At a height of some twelve
millimetres (About half an inch.--Translator's Note.), a partition
is fixed, formed of bramble saw-dust and of a green paste obtained by
masticating particles of the leaves of some plant that has not yet
been identified. This gives a second storey, which in its turn receives
provisions and an egg, the second in order of primogeniture. And so it
goes on, storey by storey, until the cylinder is full. Then a thick plug
of the same green material of which the partitions are formed closes the
home and keeps out marauders.

In this common cradle, the chronological order of births is perfectly
clear. The first-born of the family is at the bottom of the series; the
last-born is at the top, near the closed door. The others follow from
bottom to top in the same order in which they followed in point of
time. The laying is numbered automatically; each cocoon tells us its
respective age by the place which it occupies.

To know the sexes, we must wait for the month of June. But it would be
unwise to postpone our investigations until that period. Osmia-nests are
not so common that we can hope to pick one up each time that we go out
with that object; besides, if we wait for the hatching-period before
examining the brambles, it may happen that the order has been disturbed
through some insects' having tried to make their escape as soon as
possible after bursting their cocoons; it may happen that the male
Osmiae, who are more forward than the females, are already gone. I
therefore set to work a long time beforehand and devote my leisure in
winter to these investigations.

The bramble-sticks are split and the cocoons taken out one by one and
methodically transferred to glass tubes, of approximately the same
diameter as the native cylinder. These cocoons are arranged one on
top of the other in exactly the same order that they occupied in the
bramble; they are separated from one another by a cotton plug, an
insuperable obstacle to the future insect. There is thus no fear that
the contents of the cells may become mixed or transposed; and I am saved
the trouble of keeping a laborious watch. Each insect can hatch at its
own time, in my presence or not: I am sure of always finding it in
its place, in its proper order, held fast fore and aft by the cotton
barrier. A cork or sorghum-pith partition would not fulfil the same
purpose: the insect would perforate it and the register of births would
be muddled by changes of position. Any reader wishing to undertake
similar investigations will excuse these practical details, which may
facilitate his work.

We do not often come upon complete series, comprising the whole laying,
from the first-born to the youngest. As a rule, we find part of a
laying, in which the number of cocoons varies greatly, sometimes falling
as low as two, or even one. The mother has not deemed it advisable to
confide her whole family to a single bramble-stump; in order to make the
exit less toilsome, or else for reasons which escape me, she has left
the first home and elected to make a second home, perhaps a third or
more.

We also find series with breaks in them. Sometimes, in cells distributed
at random, the egg has not developed and the provisions have remained
untouched, but mildewed; sometimes, the larva has died before spinning
its cocoon, or after spinning it. Lastly, there are parasites, such
as the Unarmed Zonitis (Zonitis mutica, one of the
Oil-beetles.--Translator's Note.) and the Spotted Sapyga (A
Digger-wasp.--Translator's Note.), who interrupt the series by
substituting themselves for the original occupant. All these disturbing
factors make it necessary to examine a large number of nests of the
Three-pronged Osmia, if we would obtain a definite result.

I have been studying the bramble-dwellers for seven or eight years and I
could not say how many strings of cocoons have passed through my hands.
During a recent winter, in view particularly of the distribution of the
sexes, I collected some forty of this Osmia's nests, transferred their
contents into glass tubes and made a careful summary of the sexes.
I give some of my results. The figures start in their order from the
bottom of the tunnel dug in the bramble and proceed upwards to the
orifice. The figure 1 therefore denotes the first-born of the series,
the oldest in date; the highest figure denotes the last-born. The letter
M, placed under the corresponding figure, represents the male and the
letter F the female sex.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 F F M F M F M M F F F F M F M

This is the longest series that I have ever been able to procure. It is
also complete, inasmuch as it comprises the entire laying of the Osmia.
My statement requires explaining, otherwise it would seem impossible to
know whether a mother whose acts one has not watched, nay more, whom
one has never seen, has or has not finished laying her eggs. The
bramble-stump under consideration leaves a free space of nearly four
inches above the continuous string of cocoons. Beyond it, at the actual
orifice, is the terminal stopper, the thick plug which closes the
entrance to the gallery. In this empty portion of the tunnel there is
ample accommodation for numerous cocoons. The fact that the mother has
not made use of it proves that her ovaries were exhausted; for it is
exceedingly unlikely that she has abandoned first-rate lodgings to
go laboriously digging a new gallery elsewhere and there continue her
laying.

You may say that, if the unoccupied space marks the end of the laying,
nothing tells us that the beginning is actually at the bottom of the
cul-de-sac, at the other end of the tunnel. You may also say that the
laying is done in shifts, separated by intervals of rest. The space left
empty in the channel would mean that one of these shifts was finished
and not that there were no more eggs ripe for hatching. In answer
to these very plausible explanations, I will say that, the sum of my
observations--and they have been extremely numerous--is that the total
number of eggs laid not only by the Osmiae but by a host of other Bees
fluctuates round about fifteen.

Besides, when we consider that the active life of these insects lasts
hardly a month; when we remember that this period of activity is
disturbed by dark, rainy or very windy days, during which all work is
suspended; when lastly we ascertain, as I have done ad nauseam in the
case of the Three-horned Osmia, the time required for building and
victualling a cell, it becomes obvious that the total laying must be
kept within narrow bounds and that the mother has no time to lose if she
wishes to get fifteen cells satisfactorily built in three or four weeks
interrupted by compulsory rests. I shall give some facts later which
will dispel your doubts, if any remain.

I assume, therefore, that a number of eggs bordering on fifteen
represents the entire family of an Osmia, as it does of many other Bees.

Let us consult some other complete series. Here are two:

1 2 3 4 5 6 7 8 9 10 11 12 13 F F M F M F M F F F F M F F M F F F M F F
M F M

In both cases, the laying is taken as complete, for the same reasons as
above.

We will end with some series that appear to me incomplete, in view of
the small number of cells and the absence of any free space above the
pile of cocoons:

1 2 3 4 5 6 7 8 M M F M M M M M M M F M F M M M F M F F M M M M M F M F
F F F M M M F M

These examples are more than sufficient. It is quite evident that the
distribution of the sexes is not governed by any rule. All that I can
say on consulting the whole of my notes, which contain a good many
instances of complete layings--most of them, unfortunately, spoilt
through gaps caused by parasites, the death of the larva, the failure of
the egg to hatch and other accidents--all that I can say in general is
that the complete series begins with females and nearly always ends with
males. The incomplete series can teach us nothing in this respect,
for they are only fragments starting we know not whence; and it is
impossible to tell whether they should be ascribed to the beginning, to
the end, or to an intermediate period of the laying. To sum up: in the
laying of the Three-pronged Osmia, no order governs the succession of
the sexes; only, the series has a marked tendency to begin with females
and to finish with males.

The brambles, in my district, harbour two other Osmiae, both of much
smaller size: O. detrita, PEREZ, and O. parvula, DUF. The first is very
common, the second very rare; and until now I have found only one of
her nests, placed above a nest of O. detrita, in the same bramble. Here,
instead of the lack of order in the distribution of the sexes which we
find with O. tridentata, we have an order remarkable for consistency
and simplicity. I have before me the list of the series of O. detrita
collected last winter. Here are some of them:

1. A series of twelve: seven females, beginning with the bottom of the
tunnel, and then five males.

2. A series of nine: three females first, then six males.

3. A series of eight: five females followed by three males.

4. A series of eight: seven females followed by one male.

5. A series of eight: one female followed by seven males.

6. A series of seven: six females followed by one male.

The first series might very well be complete. The second and fifth
appear to be the end of layings, of which the beginning has taken place
elsewhere, in another bramble-stump. The males predominate and finish
off the series. Nos. 3, 4 and 6, on the other hand, look like the
beginnings of layings: the females predominate and are at the head of
the series. Even if these interpretations should be open to doubt, one
result at least is certain: with O. detrita, the laying is divided into
two groups, with no intermingling of the sexes; the first group laid
yields nothing but females, the second, or more recent, yields nothing
but males.

What was only a sort of attempt with the Three-pronged Osmia--who, it is
true, begins with females and ends with males, but muddles up the order
and mixes the two sexes anyhow between the extreme points--becomes a
regular law with her kinswoman. The mother occupies herself at the start
with the stronger sex, the more necessary, the better-gifted, the female
sex, to which she devotes the first flush of her laying and the fullness
of her vigour; later, when she is perhaps already at the end of her
strength, she bestows what remains of her maternal solicitude upon the
weaker sex, the less-gifted, almost negligible male sex.

O. parvula, of whom I unfortunately possess but one series, repeats
what the previous witness has just shown us. This series, one of nine
cocoons, comprises five females followed by four males, without any
mixing of the sexes.

Next to these disgorgers of honey and gleaners of pollen-dust, it would
be well to consult other Hymenoptera, Wasps who devote themselves to the
chase and pile their cells one after the other, in a row, showing
the relative age of the cocoons. The brambles house several of these:
Solenius vagus, who stores up Flies; Psen atratus, who provides her
grubs with a heap of Plant-lice; Trypoxylon figulus, who feeds them with
Spiders.

Solenius vagus digs her gallery in a bramble-stick that is lopped short,
but still fresh and green. The house of this Fly-huntress, therefore,
suffers from damp, as the sap enters, especially on the lower floors.
This seems to me rather insanitary. To avoid the humidity, or for other
reasons which escape me, the Solenius does not dig very far into her
bramble-stump and consequently can stack but a small number of cells in
it. A series of five cocoons gives me first four females and then one
male; another series, also of five, contains first three females, with
two males following. These are the most complete that I have for the
moment.

I reckoned on the Black Psen, or Psen atratus, whose series are pretty
long; it is a pity that they are nearly always greatly interfered with
by a parasite called Ephialtes mediator. (Cf. "The Life of the Fly":
chapter 2.--Translator's Note.) I obtained only three series free
from gaps: one of eight cocoons, comprising only females; one of six,
likewise consisting wholly of females; lastly, one of eight, formed
exclusively of males. These instances seem to show that the Psen
arranges her laying in a succession of females and a succession of
males; but they tell us nothing of the relative order of the two series.

From the Spider-huntress, Trypoxylon figulus, I learnt nothing
decisive. She appeared to me to rove about from one bramble to the next,
utilizing galleries which she has not dug herself. Not troubling to be
economical with a lodging which it has cost her nothing to acquire, she
carelessly builds a few partitions at very unequal heights, stuffs
three or four compartments with Spiders and passes on to another
bramble-stump, with no reason, so far as I know, for abandoning the
first. Her cells, therefore, occur in series that are too short to give
us any useful information.

This is all that the bramble-dwellers have to tell us; I have enumerated
the list of the principal ones in my district. We will now look
into some other Bees who arrange their cocoons in single files: the
Megachiles (Cf. Chapter 8 of the present volume.--Translator's Note.),
who cut disks out of leaves and fashion the disks into thimble-shaped
receptacles; the Anthidia (Cf. Chapters 9 and 10 of the present
volume.--Translator's Note.), who weave their honey-wallets out
of cotton-wool and arrange their cells one after the other in some
cylindrical gallery. In most cases, the home is the produce of neither
the one nor the other. A tunnel in the upright, earthy banks, the old
work of some Anthophora, is the usual dwelling. There is no great depth
to these retreats; and all my searches, zealously prosecuted during a
number of winters, procured me only series containing a small number of
cocoons, four or five at most, often one alone. And, what is quite as
serious, nearly all these series are spoilt by parasites and allow me to
draw no well-founded deductions.

I remembered finding, at rare intervals, nests of both the Anthidium and
the Megachile in the hollows of cut reeds. I thereupon installed
some hives of a new kind on the sunniest walls of my enclosure. They
consisted of stumps of the great reed of the south, open at one end,
closed at the other by the natural knot and gathered into a sort
of enormous pan-pipe, such as Polyphemus might have employed. The
invitation was accepted: Osmiae, Anthidia and Megachiles came in
fairly large numbers, especially the first, to benefit by the queer
installation.

In this way I obtained some magnificent series of Anthidia and
Megachiles, running up to a dozen. There was a melancholy side to
this success. All my series, with not one exception, were ravaged by
parasites. Those of the Megachile (M. sericans, FONSCOL), who fashions
her goblets with robinia-, holm-, and terebinth-leaves, were inhabited
by Coelioxys octodentata (A Parasitic Bee.--Translator's Note.); those
of the Anthidium (A. florentinum, LATR.) were occupied by a Leucopsis.
Both kinds were swarming with a colony of pigmy parasites whose name I
have not yet been able to discover. In short, my pan-pipe hives, though
very useful to me from other points of view, taught me nothing about the
order of the sexes among the Leaf-cutters and the cotton-weavers.

I was more fortunate with three Osmiae (O. tricornis, LATR., O. cornuta,
LATR., and O. Latreillii, SPIN.), all of whom gave me splendid results,
with reed-stumps arranged either against the walls of my garden, as I
have just said, or near their customary abode, the huge nests of the
Mason-bee of the Sheds. One of them, the Three-horned Osmia, did
better still: as I have described, she built her nests in my study, as
plentifully as I could wish, using reeds, glass tubes and other retreats
of my selecting for her galleries.

We will consult this last, who has furnished me with documents beyond
my fondest hopes, and begin by asking her of how many eggs her average
laying consists. Of the whole heap of colonized tubes in my study, or
else out of doors, in the hurdle-reeds and the pan-pipe appliances, the
best-filled contains fifteen cells, with a free space above the series,
a space showing that the laying is ended, for, if the mother had any
more eggs available, she would have lodged them in the room which she
leaves unoccupied. This string of fifteen appears to be rare; it was the
only one that I found. My attempts at indoor rearing, pursued during two
years with glass tubes or reeds, taught me that the Three-horned
Osmia is not much addicted to long series. As though to decrease the
difficulties of the coming deliverance, she prefers short galleries, in
which only a part of the laying is stacked. We must then follow the same
mother in her migration from one dwelling to the next if we would obtain
a complete census of her family. A spot of colour, dropped on the Bee's
thorax with a paint-brush while she is absorbed in closing up the mouth
of the tunnel, enables us to recognize the Osmia in her various homes.

In this way, the swarm that resided in my study furnished me, in the
first year, with an average of twelve cells. Next year, the summer
appeared to be more favourable and the average became rather higher,
reaching fifteen. The most numerous laying performed under my eyes, not
in a tube, but in a succession of Snail-shells, reached the figure of
twenty-six. On the other hand, layings of between eight and ten are not
uncommon. Lastly, taking all my records together, the result is that the
family of the Osmia fluctuates round about fifteen in number.

I have already spoken of the great differences in size apparent in
the cells of one and the same series. The partitions, at first widely
spaced, draw gradually nearer to one another as they come closer to
the aperture, which implies roomy cells at the back and narrow cells in
front. The contents of these compartments are no less uneven between one
portion and another of the string. Without any exception known to me,
the large cells, those with which the series starts, have more abundant
provisions than the straitened cells with which the series ends. The
heap of honey and pollen in the first is twice or even thrice as large
as that in the second. In the last cells, the most recent in date,
the victuals are but a pinch of pollen, so niggardly in amount that we
wonder what will become of the larva with that meagre ration.

One would think that the Osmia, when nearing the end of the laying,
attaches no importance to her last-born, to whom she doles out space
and food so sparingly. The first-born receive the benefit of her
early enthusiasm: theirs is the well-spread table, theirs the spacious
apartments. The work has begun to pall by the time that the last eggs
are laid; and the last-comers have to put up with a scurvy portion of
food and a tiny corner.

The difference shows itself in another way after the cocoons are spun.
The large cells, those at the back, receive the bulky cocoons; the small
ones, those in front, have cocoons only a half or a third as big. Before
opening them and ascertaining the sex of the Osmia inside, let us wait
for the transformation into the perfect insect, which will take place
towards the end of summer. If impatience gets the better of us, we can
open them at the end of July or in August. The insect is then in the
nymphal stage; and it is easy, under this form, to distinguish the two
sexes by the length of the antennae, which are larger in the males,
and by the glassy protuberances on the forehead, the sign of the future
armour of the females. Well, the small cocoons, those in the narrow
front cells, with their scanty store of provisions, all belong to males;
the big cocoons, those in the spacious and well-stocked cells at the
back, all belong to females.

The conclusion is definite: the laying of the Three-horned Osmia
consists of two distinct groups, first a group of females and then a
group of males.

With my pan-pipe apparatus displayed on the walls of my enclosure and
with old hurdle-reeds left lying flat out of doors, I obtained the
Horned Osmia in fair quantities. I persuaded Latreille's Osmia to
build her nest in reeds, which she did with a zeal which I was far from
expecting. All that I had to do was to lay some reed-stumps horizontally
within her reach, in the immediate neighbourhood of her usual haunts,
namely, the nests of the Mason-bee of the Sheds. Lastly, I succeeded
without difficulty in making her build her nests in the privacy of my
study, with glass tubes for a house. The result surpassed my hopes.

With both these Osmiae, the division of the gallery is the same as
with the Three-horned Osmia. At the back are large cells with plentiful
provisions and widely-spaced partitions; in front, small cells, with
scanty provisions and partitions close together. Also, the larger cells
supplied me with big cocoons and females; the smaller cells gave me
little cocoons and males. The conclusion therefore is exactly the same
in the case of all three Osmiae.

Before dismissing the Osmiae, let us devote a moment to their cocoons, a
comparison of which, in the matter of bulk, will furnish us with fairly
accurate evidence as to the relative size of the two sexes, for the
thing contained, the perfect insect, is evidently proportionate to the
silken wrapper in which it is enclosed. These cocoons are oval-shaped
and may be regarded as ellipsoids formed by a revolution around the
major axis. The volume of one of these solids is expressed in the
following formula:

4 / 3 x pi x a x (b squared),

in which 2a is the major axis and 2b the minor axis.

Now, the average dimensions of the cocoons of the Three-horned Osmia are
as follows:

2a = 13 mm. (.507 inch.--Translator's Note.), 2b = 7 mm. (.273
inch.--Translator's Note.) in the females;

2a = 9 mm. (.351 inch.--Translator's Note.), 2b = 5 mm. (.195
inch.--Translator's Note.) in the males.

The ratio therefore between 13 x 7 x 7 = 637 and 9 x 5 x 5 = 225 will be
more or less the ratio between the sizes of the two sexes. This ratio
is somewhere between 2 to 1 and 3 to 1. The females therefore are two or
three times larger than the males, a proportion already suggested by a
comparison of the mass of provisions, estimated simply by the eye.

The Horned Osmia gives us the following average dimensions:

2a = 15 mm. (.585 inch.--Translator's Note.), 2b = 9 mm. (.351
inch.--Translator's Note.) in the females;

2a = 12 mm. (.468 inch.--Translator's Note.), 2b = 7 mm. (.273
inch.--Translator's Note.) in the males.

Once again, the ratio between 15 x 9 x 9 = 1215 and 12 x 7 x 7 = 588
lies between 2 to 1 and 3 to 1.

Besides the Bees who arrange their laying in a row, I have consulted
others whose cells are grouped in a way that makes it possible to
ascertain the relative order of the two sexes, though not quite so
precisely. One of these is the Mason-bee of the Walls. I need not
describe again her dome-shaped nest, built on a pebble, which is now so
well-known to us. (Cf. "The Mason-bees": chapter 1.--Translator's Note.)

Each mother chooses her stone and works on it in solitude. She is an
ungracious landowner and guards her site jealously, driving away any
Mason who even looks as though she might alight on it. The inhabitants
of the same nest are therefore always brothers and sisters; they are the
family of one mother.

Moreover, if the stone presents a large enough surface--a condition
easily fulfilled--the Mason-bee has no reason to leave the support
on which she began her laying and go in search of another whereon to
deposit the rest of her eggs. She is too thrifty of her time and of her
mortar to involve herself in such expenditure except for grave reasons.
Consequently, each nest, at least when it is new, when the Bee herself
has laid the first foundations, contains the entire laying. It is a
different thing when an old nest is restored and made into a place for
depositing the eggs. I shall come back later to such houses.

A newly-built nest then, with rare exceptions, contains the entire
laying of one female. Count the cells and we shall have the total list
of the family. Their maximum number fluctuates round about fifteen.
The most luxuriant series will occasionally reach as many as eighteen,
though these are very scarce.

When the surface of the stone is regular all around the site of the
first cell, when the mason can add to her building with the same
facility in every direction, it is obvious that the groups of cells,
when finished, will have the oldest in the central portion and the more
recent in the surrounding portion. Because of this juxtaposition of
the cells, which serve partly as a wall to those which come next, it is
possible to form some estimate of the chronological order of the cells
in the Chalicodoma's nest and thus to discover the sequence of the two
sexes.

In winter, by which time the Bee has long been in the perfect state, I
collect Chalicodoma-nests, removing them bodily from their support with
a few smart sideward taps of the hammer on the pebbles. At the base of
the mortar dome the cells are wide agape and display their contents. I
take the cocoon from its box, open it and take note of the sex of the
insect enclosed.

I should probably be accused of exaggeration if I mentioned the total
number of the nests which I have gathered and the cells which I have
inspected by this method during the last six or seven years. I will
content myself with saying that the harvest of a single morning
sometimes consisted of as many as sixty nests of the Mason-bee. I had to
have help in carrying home my spoils, even though the nests were removed
from their stones on the spot.

From the enormous number of nests which I have examined, I am able to
state that, when the cluster is regular, the female cells occupy the
centre and the male cells the edges. Where the irregularity of the
pebble has prevented an even distribution around the initial point, the
same rule has been observed. A male cell is never surrounded on every
side by female cells: either it occupies the edges of the nest, or else
it adjoins, at least on some sides, other male cells, of which the last
form part of the exterior of the cluster. As the surrounding cells are
obviously of a later date than the inner cells, it follows that the
Mason-bee acts like the Osmiae: she begins her laying with females
and ends it with males, each of the sexes forming a series of its own,
independent of the other.

Some further circumstances add their testimony to that of the surrounded
and surrounding cells. When the pebble projects sharply and forms a sort
of dihedral angle, one of whose faces is more or less vertical and the
other horizontal, this angle is a favourite site with the Mason, who
thus finds greater stability for her edifice in the support given her by
the double plane. These sites appear to me to be in great request with
the Chalicodoma, considering the number of nests which I find thus
doubly supported. In nests of this kind, all the cells, as usual, have
their foundations fixed to the horizontal surface; but the first row,
the row of cells first built, stands with its back against the vertical
surface.

Well, these older cells, which occupy the actual edge of the dihedral
angle, are always female, with the exception of those at either end of
the row, which, as they belong to the outside, may be male cells. In
front of this first row come others. The female cells occupy the middle
portion and the male the ends. Finally, the last row, closing in the
remainder, contains only male cells. The progress of the work is very
visible here: the Mason has begun by attending to the central group of
female cells, the first row of which occupies the dihedral angle, and
has finished her task by distributing the male cells round the outside.

If the perpendicular face of the dihedral angle be high enough, it
sometimes happens that a second row of cells is placed above the first
row backing on to that plane; a third row occurs less often. The nest is
then one of several storeys. The lower storeys, the older, contain only
females; the upper, the more recent storey, contains none but males. It
goes without saying that the surface layer, even of the lower storeys,
can contain males without invalidating the rule, for this layer may
always be looked upon as the Chalicodoma's last work.

Everything therefore contributes to show that, in the Mason-bee, the
females take the lead in the order of primogeniture. Theirs is the
central and best-protected part of the clay fortress; the outer part,
that most exposed to the inclemencies of the weather and to accidents,
is for the males.

The males' cells do not differ from the females' only by being placed at
the outside of the cluster; they differ also in their capacity, which is
much smaller. To estimate the respective capacities of the two sorts
of cells, I go to work as follows: I fill the empty cell with very fine
sand and pour this sand back into a glass tube measuring 5 millimetres
(.195 inch.--Translator's Note.) in diameter. From the height of the
column of sand we can estimate the comparative capacity of the two kinds
of cells. I will take one at random among my numerous examples of cells
thus gauged.

It comprises thirteen cells and occupies a dihedral angle. The female
cells give me the following figures, in millimetres, as the height of
the columns of sand:

40, 44, 43, 48, 48, 46, 47 (1.56, 1.71, 1.67, 1.87, 1.87, 1.79, 1.83
inches.--Translator's Note.),

averaging 45. (1.75 inches.--Translator's Note.)

The male cells give me:

32, 35, 28, 30, 30, 31 (1.24, 1.36, 1.09, 1.17, 1.17, 1.21
inches.--Translator's Note.),

averaging 31. (1.21 inches.--Translator's Note.)

The ratio of the capacity of the cells for the two sexes is therefore
roughly a ratio of 4 to 3. The actual contents of the cell being
proportionate to its capacity, the above ratio must also be more or
less the ratio of provisions and sizes between females and males. These
figures will assist us presently to tell whether an old cell, occupied
for a second or third time, belonged originally to a female or a male.

The Chalicodoma of the Sheds cannot give us any information on this
matter. She builds under the same eaves, in excessively populous
colonies; and it is impossible to follow the labours of any single
Mason, whose cells, distributed here and there, are soon covered up
with the work of her neighbours. All is muddle and confusion in the
individual output of the swarming throng.

I have not watched the work of the Chalicodoma of the Shrubs with close
enough attention to be able to state definitely that this Bee is a
solitary builder. Her nest is a ball of clay hanging from a bough.
Sometimes, this nest is the size of a large walnut and then appears to
be the work of one alone; sometimes, it is the size of a man's fist, in
which case I have no doubt that it is the work of several. Those bulky
nests, comprising more than fifty cells, can tell us nothing exact, as a
number of workers must certainly have collaborated to produce them.

The walnut-sized nests are more trustworthy, for everything seems to
indicate that they were built by a single Bee. Here females are found
in the centre of the group and males at the circumference, in somewhat
smaller cells, thus repeating what the Mason-bee of the Pebbles has told
us.

One clear and simple rule stands out from this collection of facts.
Apart from the strange exception of the Three-pronged Osmia, who mixes
the sexes without any order, the Bees whom I studied and probably a
crowd of others produce first a continuous series of females and then a
continuous series of males, the latter with less provisions and smaller
cells. This distribution of the sexes agrees with what we have long
known of the Hive-bee, who begins her laying with a long sequence of
workers, or sterile females, and ends it with a long sequence of
males. The analogy continues down to the capacity of the cells and the
quantities of provisions. The real females, the Queen-bees, have wax
cells incomparably more spacious than the cells of the males and receive
a much larger amount of food. Everything therefore demonstrates that we
are here in the presence of a general rule.

But does this rule express the whole truth? Is there nothing beyond a
laying in two series? Are the Osmiae, the Chalicodomae and the rest of
them fatally bound by this distribution of the sexes into two distinct
groups, the male group following upon the female group, without any
mixing of the two? Is the mother absolutely powerless to make a change
in this arrangement, should circumstances require it?

The Three-pronged Osmia already shows us that the problem is far from
being solved. In the same bramble-stump, the two sexes occur very
irregularly, as though at random. Why this mixture in the series
of cocoons of a Bee closely related to the Horned Osmia and the
Three-horned Osmia, who stack theirs methodically by separate sexes
in the hollow of a reed? What the Bee of the brambles does cannot her
kinswomen of the reeds do too? Nothing, so far as I know, can explain
this difference in a physiological act of primary importance. The three
Bees belong to the same genus; they resemble one another in general
outline, internal structure and habits; and, with this close similarity,
we suddenly find a strange dissimilarity.

There is just one thing that might possibly arouse a suspicion of the
cause of this irregularity in the Three-pronged Osmia's laying. If I
open a bramble-stump in the winter to examine the Osmia's nest, I find
it impossible, in the vast majority of cases, to distinguish positively
between a female and a male cocoon: the difference in size is so
small. The cells, moreover, have the same capacity: the diameter of the
cylinder is the same throughout and the partitions are almost always the
same distance apart. If I open it in July, the victualling-period, it is
impossible for me to distinguish between the provisions destined for the
males and those destined for the females. The measurement of the column
of honey gives practically the same depth in all the cells. We find an
equal quantity of space and food for both sexes.

This result makes us foresee what a direct examination of the two sexes
in the adult form tells us. The male does not differ materially from
the female in respect of size. If he is a trifle smaller, it is scarcely
noticeable, whereas, in the Horned Osmia and the Three-horned Osmia,
the male is only half or a third the size of the female, as we have seen
from the respective bulk of their cocoons. In the Mason-bee of the Walls
there is also a difference in size, though less pronounced.

The Three-pronged Osmia has not therefore to trouble about adjusting the
dimensions of the dwelling and the quantity of the food to the sex of
the egg which she is about to lay; the measure is the same from one end
of the series to the other. It does not matter if the sexes alternate
without order: one and all will find what they need, whatever their
position in the row. The two other Osmiae, with their great disparity
in size between the two sexes, have to be careful about the twofold
consideration of board and lodging. And that, I think, is why they begin
with spacious cells and generous rations for the homes of the females
and end with narrow, scantily-provisioned cells, the homes of the males.
With this sequence, sharply defined for the two sexes, there is less
fear of mistakes which might give to one what belongs to another. If
this is not the explanation of the facts, I see no other.

The more I thought about this curious question, the more probable it
appeared to me that the irregular series of the Three-pronged Osmia and
the regular series of the other Osmiae, of the Chalicodomae and of the
Bees in general were all traceable to a common law. It seemed to me that
the arrangement in a succession first of females and then of males did
not account for everything. There must be something more. And I was
right: that arrangement in series is only a tiny fraction of the
reality, which is remarkable in a very different way. This is what I am
going to prove by experiment.




CHAPTER 4. THE MOTHER DECIDES THE SEX OF THE EGG.

I will begin with the Mason-bee of the Pebbles. (This is the same
insect as the Mason-bee of the Walls. Cf. "The Mason-bees":
passim.--Translator's Note.) The old nests are often used, when they are
in good enough repair. Early in the season the mothers quarrel fiercely
over them; and, when one of the Bees has taken possession of the coveted
dome, she drives any stranger away from it. The old house is far from
being a ruin, only it is perforated with as many holes as it once had
occupants. The work of restoration is no great matter. The heap of earth
due to the destruction of the lid by the outgoing tenant is taken out of
the cell and flung away at a distance, atom by atom. The remnants of
the cocoon are also thrown away, but not always, for the delicate silken
wrapper sometimes adheres closely to the masonry.

The victualling of the renovated cell is now begun. Next comes the
laying; and lastly the orifice is sealed with a mortar plug. A second
cell is utilized in the same way, followed by a third and so on, one
after the other, as long as any remain unoccupied and the mother's
ovaries are not exhausted. Finally, the dome receives, mainly over the
apertures already plugged, a coat of plaster which makes the nest look
like new. If she has not finished her laying, the mother goes in search
of other old nests to complete it. Perhaps she does not decide to found
a new establishment except when she can find no second-hand dwellings,
which mean a great economy of time and labour. In short, among the
countless number of nests which I have collected, I find many more
ancient than recent ones.

How shall we distinguish one from the other? The outward aspect tells
you nothing, owing to the great care taken by the Mason to restore the
surface of the old dwelling equal to new. To resist the rigours of the
winter, this surface must be impregnable. The mother knows that and
therefore repairs the dome. Inside, it is another matter: the old nest
stands revealed at once. There are cells whose provisions, at least a
year old, are intact, but dried up or musty, because the egg has never
developed. There are others containing a dead larva, reduced by time
to a blackened, curled-up cylinder. There are some whence the perfect
insect was never able to issue: the Chalicodoma wore herself out in
trying to pierce the ceiling of her chamber; her strength failed her and
she perished in the attempt. Others again and very many are occupied
by ravagers, Leucopses (Cf. "The Mason-bees": chapter 11.--Translator's
Note.) and Anthrax-flies, who will come out a good deal later, in July.
Altogether, the house is far from having every room vacant; there are
nearly always a considerable number occupied either by parasites that
were still in the egg-stage at the time when the Mason-bee was at work
or by damaged provisions, dried grubs or Chalicodomae in the perfect
state who have died without being able to effect their deliverance.

Should all the rooms be available, a rare occurrence, there still
remains a method of distinguishing between an ancient nest and a recent
one. The cocoon, as I have said, adheres pretty closely to the walls;
and the mother does not always take away this remnant, either
because she is unable to do so, or because she considers the removal
unnecessary. Thus the base of the new cocoon is set in the bottom of the
old cocoon. This double wrapper points very clearly to two generations,
two separate years. I have even found as many as three cocoons fitting
one into another at their bases. Consequently, the nests of the
Mason-bee of the Pebbles are able to do duty for three years, if not
more. Eventually they become utter ruins, abandoned to the Spiders and
to various smaller Bees or Wasps, who take up their quarters in the
crumbling rooms.

As we see, an old nest is hardly ever capable of containing the
Mason-bee's entire laying, which calls for some fifteen apartments. The
number of rooms at her disposal is most unequal, but always very small.
It is saying much when there are enough to receive about half the
laying. Four or five cells, sometimes two or even one: that is what
the Mason usually finds in a nest that is not her own work. This large
reduction is explained when we remember the numerous parasites that live
upon the unfortunate Bee.

Now, how are the sexes distributed in those layings which are
necessarily broken up between one old nest and another? They are
distributed in such a way as utterly to upset the idea of an invariable
succession first of females and then of males, the idea which occurs
to us on examining the new nests. If this rule were a constant one, we
should be bound to find in the old domes at one time only females, at
another only males, according as the laying was at its first or at its
second stage. The simultaneous presence of the two sexes would then
correspond with the transition period between one stage and the next and
should be very unusual. On the contrary, it is very common; and, however
few cells there may be, we always find both females and males in the old
nests, on the sole condition that the compartments have the regulation
holding-capacity, a large capacity for the females, a lesser for the
males, as we have seen.

The old male cells can be recognized by their position on the outer
edges and by their capacity, measuring on an average the same as a
column of sand 31 millimetres high in a glass tube 5 millimetres wide.
(1.21 x.195 inches.--Translator's Note.) These cells contain males of
the second or third generation and none but males. In the old female
cells, those in the middle, whose capacity is measured by a similar
column of sand 45 millimetres high (1.75 inches.--Translator's Note.),
are females and none but females.

This presence of both sexes at a time, even when there are but two cells
free, one spacious and the other small, proves in the plainest fashion
that the regular distribution observed in the complete nests of recent
production is here replaced by an irregular distribution, harmonizing
with the number and holding-capacity of the chambers to be stocked. The
Mason-bee has before her, let me suppose, only five vacant cells: two
larger and three smaller. The total space at her disposal would do for
about a third of the laying. Well, in the two large cells, she puts
females; in the three small cells, she puts males.

As we find the same sort of thing in all the old nests, we must needs
admit that the mother knows the sex of the egg which she is going to
lay, because that egg is placed in a cell of the proper capacity. We can
go further and admit that the mother alters the order of succession of
the sexes at her pleasure, because her layings, between one old nest and
another, are broken up into small groups of males and females according
to the exigencies of space in the actual nest which she happens to be
occupying.

Just now, in the new nest, we saw the Mason-bee arranging her total
laying into series first of females and next of males; and here she
is, mistress of an old nest of which she has not the power to alter the
arrangement, breaking up her laying into sections comprising both sexes
just as required by the conditions imposed upon her. She therefore
decides the sex of the egg at will, for, without this prerogative, she
could not, in the chambers of the nest which she owes to chance, deposit
unerringly the sex for which those chambers were originally built; and
this happens however small the number of chambers to be filled.

When the nest is new, I think I see a reason why the Mason-bee
should seriate her laying into females and then males. Her nest is
a half-sphere. That of the Mason-bee of the Shrubs is very nearly a
sphere. Of all shapes, the spherical shape is the strongest. Now these
two nests require an exceptional power of resistance. Without protection
of any kind, they have to brave the weather, one on its pebble, the
other on its bough. Their spherical configuration is therefore very
practical.

The nest of the Mason-bee of the Walls consists of a cluster of upright
cells backing against one another. For the whole to take a spherical
form, the height of the chambers must diminish from the centre of the
dome to the circumference. Their elevation is the sine of the meridian
arc starting from the plane of the pebble. Therefore, if they are to
have any solidity, there must be large cells in the middle and small
cells at the edges. And, as the work begins with the central chambers
and ends with those on the circumference, the laying of the females,
destined for the large cells, must precede that of the males, destined
for the small cells. So the females come first and the males at the
finish.

This is all very well when the mother herself founds the dwelling, when
she lays the first rows of bricks. But, when she is in the presence
of an old nest, of which she is quite unable to alter the general
arrangement, how is she to make use of the few vacant rooms, the large
and the small alike, if the sex of the egg be already irrevocably fixed?
She can only do so by abandoning the arrangement in two consecutive
rows and accommodating her laying to the varied exigencies of the home.
Either she finds it impossible to make an economical use of the old
nest, a theory refuted by the evidence, or else she determines at will
the sex of the egg which she is about to lay.

The Osmiae themselves will furnish the most conclusive evidence on the
latter point. We have seen that these Bees are not generally miners, who
themselves dig out the foundation of their cells. They make use of the
old structures of others, or else of natural retreats, such as hollow
stems, the spirals of empty shells and various hiding-places in walls,
clay or wood. Their work is confined to repairs to the house, such
as partitions and covers. There are plenty of these retreats; and the
insect would always find first-class ones if it thought of going any
distance to look for them. But the Osmia is a stay-at-home: she returns
to her birth-place and clings to it with a patience extremely difficult
to exhaust. It is here, in this little familiar corner, that she prefers
to settle her progeny. But then the apartments are few in number and of
all shapes and sizes. There are long and short ones, spacious ones and
narrow. Short of expatriating herself, a Spartan course, she has to use
them all, from first to last, for she has no choice. Guided by these
considerations, I embarked on the experiments which I will now describe.

I have said how my study, on two separate occasions, became a populous
hive, in which the Three-horned Osmia built her nests in the various
appliances which I had prepared for her. Among these appliances, tubes,
either of glass or reed, predominated. There were tubes of all lengths
and widths. In the long tubes, entire or almost entire layings, with a
series of females followed by a series of males, were deposited. As I
have already referred to this result, I will not discuss it again. The
short tubes were sufficiently varied in length to lodge one or other
portion of the total laying. Basing my calculations on the respective
lengths of the cocoons of the two sexes, on the thickness of the
partitions and the final lid, I shortened some of these to the exact
dimensions required for two cocoons only, of different sexes.

Well, these short tubes, whether of glass or reed, were seized upon as
eagerly as the long tubes. Moreover, they yielded this splendid result:
their contents, only a part of the total laying, always began with
female and ended with male cocoons. This order was invariable; what
varied was the number of cells in the long tubes and the proportion
between the two sorts of cocoons, sometimes males predominating and
sometimes females.

The experiment is of paramount importance; and it will perhaps make the
result clearer if I quote one instance from among a multitude of similar
cases. I give the preference to this particular instance because of
the rather exceptional fertility of the laying. An Osmia marked on the
thorax is watched, day by day, from the commencement to the end of her
work. From the 1st to the 10th of May, she occupies a glass tube in
which she lodges seven females followed by a male, which ends the
series. From the 10th to the 17th of May, she colonizes a second tube,
in which she lodges first three females and then three males. From the
17th to the 25th of May, a third tube, with three females and then two
males. On the 26th of May, a fourth tube, which she abandons, probably
because of its excessive width, after laying one female in it. Lastly,
from the 26th to the 30th of May, a fifth tube, which she colonizes
with two females and three males. Total: twenty-five Osmiae, including
seventeen females and eight males. And it will not be superfluous to
observe that these unfinished series do not in any way correspond with
periods separated by intervals of rest. The laying is continuous, in so
far as the variable condition of the atmosphere allows. As soon as one
tube is full and closed, another is occupied by the Osmia without delay.

The tubes reduced to the exact length of two cells fulfilled my
expectation in the great majority of cases: the lower cell was occupied
by a female and the upper by a male. There were a few exceptions.
More discerning than I in her estimate of what was strictly necessary,
better-versed in the economy of space, the Osmia had found a way of
lodging two females where I had only seen room for one female and a
male.

This experiment speaks volumes. When confronted with tubes too small to
receive all her family, she is in the same plight as the Mason-bee
in the presence of an old nest. She thereupon acts exactly as the
Chalicodoma does. She breaks up her laying, divides it into series as
short as the room at her disposal demands; and each series begins with
females and ends with males. This breaking up, on the one hand, into
sections in all of which both sexes are represented and the division, on
the other hand, of the entire laying into just two groups, one female,
the other male, when the length of the tube permits, surely provide us
with ample evidence of the insect's power to regulate the sex of the egg
according to the exigencies of space.

And besides the exigencies of space one might perhaps venture to add
those connected with the earlier development of the males. These burst
their cocoons a couple of weeks or more before the females; they are the
first who hasten to the sweets of the almond-tree. In order to release
themselves and emerge into the glad sunlight without disturbing the
string of cocoons wherein their sisters are still sleeping, they must
occupy the upper end of the row; and this, no doubt, is the reason that
makes the Osmia end each of her broken layings with males. Being next to
the door, these impatient ones will leave the home without upsetting the
shells that are slower in hatching.

I experimented on Latreille's Osmia, using short and even very short
stumps of reed. All that I had to do was to lay them just beside the
nests of the Mason-bee of the Sheds, nests beloved by this particular
Osmia. Old, disused hurdles supplied me with reeds inhabited from end to
end by the Horned Osmia. In both cases I obtained the same results and
the same conclusions as with the Three-horned Osmia.

I return to the latter, nidifying under my eyes in some old nests of the
Mason-bee of the Walls, which I had placed within her reach, mixed up
with the tubes. Outside my study, I had never yet seen the Three-horned
Osmia adopt that domicile. This may be due to the fact that these nests
are isolated one by one in the fields; and the Osmia, who loves to feel
herself surrounded by her kin and to work in plenty of company, refuses
them because of this isolation. But on my table, finding them close
to the tubes in which the others are working, she adopts them without
hesitation.

The chambers presented by those old nests are more or less spacious
according to the thickness of the coat of mortar which the Chalicodoma
has laid over the assembled chambers. To leave her cell, the Mason-bee
has to perforate not only the plug, the lid built at the mouth of the
cell, but also the thick plaster wherewith the dome is strengthened at
the end of the work. The perforation results in a vestibule which gives
access to the chamber itself. It is this vestibule which is sometimes
longer and sometimes shorter, whereas the corresponding chamber is of
almost constant dimensions, in the case of the same sex, of course.

We will first consider the short vestibule, at the most large enough to
receive the plug with which the Osmia will close up the lodging. There
is then nothing at her disposal except the cell proper, a spacious
apartment in which one of the Osmia's females will find ample
accommodation, for she is much smaller than the original occupant of the
chamber, no matter the sex; but there is not room for two cocoons at
a time, especially in view of the space taken up by the intervening
partition. Well, in those large, well-built chambers, formerly the homes
of Chalicodomae, the Osmia settles females and none but females.

Let us now consider the long vestibule. Here, a partition is
constructed, encroaching slightly on the cell proper, and the residence
is divided into two unequal storeys, a large room below, housing a
female, and a narrow cabin above, containing a male.

When the length of the vestibule permits, allowing for the space
required by the outer stopper, a third storey is built, smaller than the
second; and another male is lodged in this cramped corner. In this way
the old nest of the Mason-bee of the Pebbles is colonized, cell after
cell, by a single mother.

The Osmia, as we see, is very frugal of the lodging that has fallen to
her share; she makes the best possible use of it, giving to the females
the spacious chambers of the Mason-bee and to the males the narrow
vestibules, subdivided into storeys when this is feasible. Economy of
space is the chief consideration, since her stay-at-home tastes do not
allow her to indulge in distant quests. She has to employ the site which
chance places at her disposal just as it is, now for a male and now for
a female. Here we see displayed, more clearly than ever, her power of
deciding the sex of the egg, in order to adapt it judiciously to the
conditions of the house-room available.

I had offered at the same time to the Osmiae in my study some old
nests of the Mason-bee of the Shrubs, which are clay spheroids with
cylindrical cavities in them. These cavities are formed, as in the old
nests of the Mason-bee of the Pebbles, of the cell properly so-called
and of the exit-way which the perfect insect cut through the outer
coating at the time of its deliverance. Their diameter is about seven
millimetres (.273 inch.--Translator's Note.); their depth at the centre
of the heap is 23 millimetres (.897 inch.--Translator's Note.); and at
the edge averages 14 millimetres (.546 inch.--Translator's Note.)

The deep central cells receive only the females of the Osmia; sometimes
even the two sexes together, with a partition in the middle, the female
occupying the lower and the male the upper storey. True, in such cases
economy of space is strained to the utmost, the apartments provided by
the Mason-bee of the Shrubs being very small as it is, despite their
entrance-halls. Lastly, the deeper cavities on the circumference are
allotted to females and the shallower to males.

I will add that a single mother peoples each nest and also that she
proceeds from cell to cell without troubling to ascertain the depth. She
goes from the centre to the edges, from the edges to the centre, from a
deep cavity to a shallow cavity and vice versa, which she would not
do if the sexes were to follow upon each other in a settled order. For
greater certainty, I numbered the cells of one nest as each of them was
closed. On opening them later, I was able to see that the sexes were
not subjected to a chronological arrangement. Females were succeeded by
males and these by females without its being possible for me to make out
any regular sequence. Only--and this is the essential point--the deep
cavities were allotted to the females and the shallow ones to the males.

We know that the Three-horned Osmia prefers to haunt the habitations of
the Bees who nidify in populous colonies, such as the Mason-bee of the
Sheds and the Hairy-footed Anthophora. Exercising the very greatest
care, I broke up some great lumps of earth removed from the banks
inhabited by the Anthophora and sent to me from Carpentras by my dear
friend and pupil M. Devillario. I examined them conscientiously in the
quiet of my study. I found the Osmia's cocoons arranged in short series,
in very irregular passages, the original work of which is due to the
Anthophora. Touched up afterwards, made larger or smaller, lengthened
or shortened, intersected with a network of crossings by the numerous
generations that had succeeded one another in the same city, they formed
an inextricable labyrinth.

Sometimes these corridors did not communicate with any adjoining
apartment; sometimes they gave access to the spacious chamber of the
Anthophora, which could be recognized, in spite of its age, by its oval
shape and its coating of glazed stucco. In the latter case, the bottom
cell, which once constituted, by itself, the chamber of the Anthophora,
was always occupied by a female Osmia. Beyond it, in the narrow
corridor, a male was lodged, not seldom two, or even three. Of course,
clay partitions, the work of the Osmia, separated the different
inhabitants, each of whom had his own storey, his own closed cell.

When the accommodation consisted of no more than a simple cylinder,
with no state-bedroom at the end of it--a bedroom always reserved for
a female--the contents varied with the diameter of the cylinder. The
series, of which the longest were series of four, included, with a
wider diameter, first one or two females, then one or two males. It also
happened, though rarely, that the series was reversed, that is to say,
it began with males and ended with females. Lastly, there were a good
many isolated cocoons, of one sex or the other. When the cocoon was
alone and occupied the Anthophora's cell, it invariably belonged to a
female.

I have observed the same thing in the nests of the Mason-bee of the
Sheds, but not so easily. The series are shorter here, because the
Mason-bee does not bore galleries but builds cell upon cell. The work
of the whole swarm thus forms a stratum of cells that grows thicker from
year to year. The corridors occupied by the Osmia are the holes which
the Mason-bee dug in order to reach daylight from the deep layers.
In these short series, both sexes are usually present; and, if the
Mason-bee's chamber is at the end of the passage, it is inhabited by a
female Osmia.

We come back to what the short tubes and the old nests of the Mason-bee
of the Pebbles have already taught us. The Osmia who, in tubes of
sufficient length, divides her whole laying into a continuous sequence
of females and a continuous sequence of males, now breaks it up into
short series in which both sexes are present. She adapts her sectional
layings to the exigencies of a chance lodging; she always places a
female in the sumptuous chamber which the Mason-bee or the Anthophora
occupied originally.

Facts even more striking are supplied by the old nests of the Masked
Anthophora (A. personata, ILLIG.), old nests which I have seen utilized
by the Horned Osmia and the Three-horned Osmia at the same time. Less
frequently, the same nests serve for Latreille's Osmia. Let us first
describe the Masked Anthophora's nests.

In a steep bank of sandy clay, we find a set of round, wide-open holes.
There are generally only a few of them, each about half an inch in
diameter. They are the entrance-doors leading to the Anthophora's abode,
doors always left open, even after the building is finished. Each of
them gives access to a short passage, sometimes straight, sometimes
winding, nearly horizontal, polished with minute care and varnished with
a sort of white glaze. It looks as if it had received a thin coat of
whitewash. On the inner surface of this passage, in the thickness of
the earthy bank, spacious oval niches have been excavated, communicating
with the corridor by means of a narrow bottle-neck, which is closed,
when the work is done, with a substantial mortar stopper. The Anthophora
polishes the outside of this stopper so well, smooths its surface so
perfectly, bringing it to the same level as that of the passage, is so
careful to give it the white tint of the rest of the wall that, when
the job is finished, it becomes absolutely impossible to distinguish the
entrance-door corresponding with each cell.

The cell is an oval cavity dug in the earthy mass. The wall has the
same polish, the same chalky whiteness as the general passage. But the
Anthophora does not limit herself to digging oval niches: to make her
work more solid, she pours over the walls of the chamber a salivary
liquid which not only whitens and varnishes but also penetrates to a
depth of some millimetres into the sandy earth, which it turns into
a hard cement. A similar precaution is taken with the passage; and
therefore the whole is a solid piece of work capable of remaining in
excellent condition for years.

Moreover, thanks to the wall hardened by the salivary fluid, the
structure can be removed from its matrix by chipping it carefully away.
We thus obtain, at least in fragments, a serpentine tube from which
hangs a single or double row of oval nodules that look like large grapes
drawn out lengthwise. Each of these nodules is a cell, the entrance to
which, carefully hidden, opens into the tube or passage. When she wishes
to leave her cell, in the spring, the Anthophora destroys the mortar
disk that closes the jar and thus reaches the general corridor, which
is quite open to the outer air. The abandoned nest provides a series of
pear-shaped cavities, of which the distended part is the old cell and
the contracted part the exit-neck, rid of its stopper.

These pear-shaped hollows form splendid lodgings, impregnable
strongholds, in which the Osmiae find a safe and commodious retreat for
their families. The Horned Osmia and the Three-horned Osmia establish
themselves there at the same time. Although it is a little too large for
her, Latrielle's Osmia also appears very well satisfied with it.

I have examined some forty of the superb cells utilized by each of the
first two. The great majority are divided into two storeys by means of
a transversal partition. The lower storey includes the larger portion
of the Anthophora's cell; the upper storey includes the rest of the
cell and a little of the bottle-neck that surmounts it. The two-roomed
dwelling is closed, in the passage, by a shapeless, bulky mass of dried
mud. What a clumsy artist the Osmia is, compared with the Anthophora!
Against the exquisite work of the Anthophora, partition and plug strike
a note as hideously incongruous as a lump of dirt on polished marble.

The two apartments thus obtained are of a very unequal capacity, which
at once strikes the observer. I measured them with my five-millimetre
tube. On an average, the bottom one is represented by a column of sand
50 millimetres deep (1.95 inches.--Translator's Note.) and the top one
by a column of 15 millimetres (.585 inch.--Translator's Note.). The
holding-capacity of the one is therefore about three times as large as
that of the other. The cocoons enclosed present the same disparity. The
bottom one is big, the top one small. Lastly, the lower one belongs to a
female Osmia and the upper to a male Osmia.

Occasionally the length of the bottle-neck allows of a fresh arrangement
and the cavity is divided into three storeys. The bottom one, which is
always the most spacious, contains a female; the two above, both smaller
than the first and one smaller than the other, contain males.

Let us keep to the first case, which is always the most frequent. The
Osmia is in the presence of one of these pear-shaped hollows. It is a
find that must be employed to the best advantage: a prize of this sort
is rare and falls only to fortune's favourites. To lodge two females
in it at once is impossible; there is not sufficient room. To lodge two
males in it would be undue generosity to a sex that is entitled to but
the smallest consideration. Besides, the two sexes must be represented
in almost equal numbers. The Osmia decides upon one female, whose
portion shall be the better room, the lower one, which is larger,
better-protected and more nicely polished, and one male, whose portion
shall be the upper storey, a cramped attic, uneven and rugged in the
part which encroaches on the bottle-neck. This decision is proved by
numerous undeniable facts. Both Osmiae therefore can choose the sex
of the egg about to be laid, seeing that they are now breaking up the
laying into groups of two, a female and a male, as required by the
conditions of the lodging.

I have only once found Latreille's Osmia established in the nest of the
Masked Anthophora. She had occupied but a small number of cells, because
the others were not free, being inhabited by the Anthophora. The cells
in question were divided into three storeys by partitions of green
mortar; the lower storey was occupied by a female, the two others by
males, with smaller cocoons.

I came to an even more remarkable example. Two Anthidia of my district,
A. septemdentatum, LATR., and A. bellicosum, LEP., adopt as the home of
their offspring the empty shells of different snails: Helix aspersa, H.
algira, H. nemoralis, H. caespitum. The first-named, the Common Snail,
is the most often used, under the stone-heaps and in the crevices of old
walls. Both Anthidia colonize only the second whorl of the spiral. The
central part is too small and remains unoccupied. Even so with the front
whorl, the largest, which is left completely empty, so much so that, on
looking through the opening, it is impossible to tell whether the shell
does or does not contain the Bee's nest. We have to break this last
whorl if we would perceive the curious nest tucked away in the spiral.

We then find first a transversal partition, formed of tiny bits of
gravel cemented by a putty made from resin, which is collected in fresh
drops from the oxycedrus and the Aleppo pine. Beyond this is a stout
barricade made up of rubbish of all kinds: bits of gravel, scraps of
earth, juniper-needles, the catkins of the conifers, small shells,
dried excretions of Snails. Next come a partition of pure resin, a large
cocoon in a roomy chamber, a second partition of pure resin and, lastly,
a smaller cocoon in a narrow chamber. The inequality of the two cells is
the necessary consequence of the shape of the shell, whose inner space
gains rapidly in width as the spiral gets nearer to the orifice. Thus,
by the mere general arrangement of the home and without any work on the
Bee's part beyond some slender partitions, a large room is marked out in
front and a much smaller room at the back.

By a very remarkable exception, which I have mentioned casually
elsewhere, the males of the genus Anthidium are generally larger than
the females; and this is the case with the two species in particular
that divide the Snail's spiral with resin partitions. I collected some
dozens of nests of both species. In at least half the cases, the two
sexes were present together; the female, the smaller, occupied the front
cell and the male, the bigger, the back cell. Other cells, which were
smaller or too much obstructed at the back by the dried-up remains of
the Mollusc, contained only one cell, occupied at one time by a female
and at another by a male. A few, lastly, had both cells inhabited now by
two males and now by two females. The most frequent arrangement was the
simultaneous presence of both sexes, with the female in front and the
male behind. The Anthidia who make resin-dough and live in Snail-shells
can therefore alternate the sexes regularly to meet the exigencies of
the spiral dwelling-house.

One more thing and I have done. My apparatus of reeds, fixed against the
walls of the garden, supplied me with a remarkable nest of the Horned
Osmia. The nest is established in a bit of reed 11 millimetres wide
inside. (.429 inch--Translator's Note.) It comprises thirteen cells and
occupies only half the cylinder, although the orifice is plugged with
the usual stopper. The laying therefore seems here to be complete.

Well, this laying is arranged in a most singular fashion. There is
first, at a suitable distance from the bottom or the node of the reed, a
transversal partition, perpendicular to the axis of the tube. This marks
off a cell of unusual size, in which a female is lodged. After that,
in view of the excessive width of the tunnel, which is too great for
a series in single file, the Osmia appears to alter her mind. She
therefore builds a partition perpendicular to the transversal partition
which she has just constructed and thus divides the second storey into
two rooms, a larger room, in which she lodges a female, and a smaller,
in which she lodges a male. She next builds a second transversal
partition and a second longitudinal partition perpendicular to it. These
once more give two unequal chambers, stocked likewise, the large one
with a female, the smaller one with a male.

From this third storey onwards, the Osmia abandons geometrical
accuracy; the architect seems to be a little out in her reckoning. The
transversal partitions become more and more slanting and the work
grows irregular, but always with a sprinkling of large chambers for the
females and small chambers for the males. Three females and two males
are housed in this way, the sexes alternating.

By the time that the base of the eleventh cell is reached, the
transversal partition is once more almost perpendicular to the axis.
Here what happened at the bottom is repeated. There is no longitudinal
partition; and the spacious cell, covering the whole diameter of the
cylinder, receives a female. The edifice ends with two transversal
partitions and one longitudinal partition, which mark out, on the same
level, chambers twelve and thirteen, both of which contain males.

There is nothing more curious than this mixing of the two sexes, when
we know with what precision the Osmia separates them in a linear series,
where the narrow width of the cylinder demands that the cells shall be
set singly, one above the other. Here, the Bee is making use of a tube
whose diameter is not suited to her work; she is constructing a complex
and difficult edifice, which perhaps would not possess the necessary
solidity if the ceilings were too broad. The Osmia therefore supports
these ceilings with longitudinal partitions; and the unequal chambers
resulting from the introduction of these partitions receive females at
one time and males at another, according to their capacity.




CHAPTER 5. PERMUTATIONS OF SEX.

The sex of the egg is optional. The choice rests with the mother, who is
guided by considerations of space and, according to the accommodation
at her disposal, which is frequently fortuitous and incapable of
modification, places a female in this cell and a male in that, so that
both may have a dwelling of a size suited to their unequal development.
This is the unimpeachable evidence of the numerous and varied facts
which I have set forth. People unfamiliar with insect anatomy--the
public for whom I write--would probably give the following explanation
of this marvellous prerogative of the Bee: the mother has at her
disposal a certain number of eggs, some of which are irrevocably female
and the others irrevocably male: she is able to pick out of either group
the one which she wants at the actual moment; and her choice is decided
by the holding capacity of the cell that has to be stocked. Everything
would then be limited to a judicious selection from the heap of eggs.

Should this idea occur to him, the reader must hasten to reject it.
Nothing could be more false, as the merest reference to anatomy will
show. The female reproductive apparatus of the Hymenoptera consists
generally of six ovarian tubes, something like glove-fingers, divided
into bunches of three and ending in a common canal, the oviduct, which
carries the eggs outside. Each of these glove-fingers is fairly wide
at the base, but tapers sharply towards the tip, which is closed.
It contains, arranged in a row, one after the other, like beads on a
string, a certain number of eggs, five or six for instance, of which the
lower ones are more or less developed, the middle ones half-way towards
maturity, and the upper ones very rudimentary. Every stage of evolution
is here represented, distributed regularly from bottom to top, from the
verge of maturity to the vague outlines of the embryo. The sheath clasps
its string of ovules so closely that any inversion of the order is
impossible. Besides, an inversion would result in a gross absurdity: the
replacing of a riper egg by another in an earlier stage of development.

Therefore, in each ovarian tube, in each glove-finger, the emergence of
the eggs occurs according to the order governing their arrangement in
the common sheath; and any other sequence is absolutely impossible.
Moreover, at the nesting period, the six ovarian sheaths, one by one and
each in its turn, have at their base an egg which in a very short time
swells enormously. Some hours or even a day before the laying, that egg
by itself represents or even exceeds in bulk the whole of the ovigenous
apparatus. This is the egg which is on the point of being laid. It is
about to descend into the oviduct, in its proper order, at its proper
time; and the mother has no power to make another take its place. It is
this egg, necessarily this egg and no other, that will presently be laid
upon the provisions, whether these be a mess of honey or a live prey; it
alone is ripe, it alone is at the entrance to the oviduct; none of the
others, since they are farther back in the row and not at the right
stage of development, can be substituted at this crisis. Its birth is
inevitable.

What will it yield, a male or a female? No lodging has been prepared,
no food collected for it; and yet both food and lodging have to be in
keeping with the sex that will proceed from it. And here is a much more
puzzling condition: the sex of that egg, whose advent is predestined,
has to correspond with the space which the mother happens to have found
for a cell. There is therefore no room for hesitation, strange though
the statement may appear: the egg, as it descends from its ovarian tube,
has no determined sex. It is perhaps during the few hours of its rapid
development at the base of its ovarian sheath, it is perhaps on its
passage through the oviduct that it receives, at the mother's pleasure,
the final impress that will produce, to match the cradle which it has to
fill, either a female or a male.

Thereupon the following question presents itself. Let us admit that,
when the normal conditions remain, a laying would have yielded m females
and n males. Then, if my conclusions are correct, it must be in the
mother's power, when the conditions are different, to take from the m
group and increase the n group to the same extent; it must be possible
for her laying to be represented as m-1, m-2, m-3, etc. females and by
n+1, n+2, n+3, etc. males, the sum of m+n remaining constant, but one of
the sexes being partly permuted into the other. The ultimate conclusion
even cannot be disregarded: we must admit a set of eggs represented
by m-m, or zero, females and of n+m males, one of the sexes being
completely replaced by the other. Conversely, it must be possible for
the feminine series to be augmented from the masculine series to the
extent of absorbing it entirely. It was to solve this question and some
others connected with it that I undertook, for the second time, to rear
the Three-horned Osmia in my study.

The problem on this occasion is a more delicate one; but I am
also better-equipped. My apparatus consists of two small, closed
packing-cases, with the front side of each pierced with forty holes,
in which I can insert my glass tubes and keep them in a horizontal
position. I thus obtain for the Bees the darkness and mystery which suit
their work and for myself the power of withdrawing from my hive, at any
time, any tube that I wish, with the Osmia inside, so as to carry it
to the light and follow, if need be with the aid of the lens, the
operations of the busy worker. My investigations, however frequent and
minute, in no way hinder the peaceable Bee, who remains absorbed in her
maternal duties.

I mark a plentiful number of my guests with a variety of dots on the
thorax, which enables me to follow any one Osmia from the beginning
to the end of her laying. The tubes and their respective holes are
numbered; a list, always lying open on my desk, enables me to note from
day to day, sometimes from hour to hour, what happens in each tube and
particularly the actions of the Osmiae whose backs bear distinguishing
marks. As soon as one tube is filled, I replace it by another. Moreover,
I have scattered in front of either hive a few handfuls of empty
Snail-shells, specially chosen for the object which I have in view.
Reasons which I will explain later led me to prefer the shells of Helix
caespitum. Each of the shells, as and when stocked, received the date
of the laying and the alphabetical sign corresponding with the Osmia to
whom it belonged. In this way, I spent five or six weeks in continual
observation. To succeed in an enquiry, the first and foremost condition
is patience. This condition I fulfilled; and it was rewarded with the
success which I was justified in expecting.

The tubes employed are of two kinds. The first, which are cylindrical
and of the same width throughout, will be of use for confirming the
facts observed in the first year of my experiments in indoor rearing.
The others, the majority, consist of two cylinders which are of very
different diameters, set end to end. The front cylinder, the one which
projects a little way outside the hive and forms the entrance-hole,
varies in width between 8 and 12 millimetres. (Between.312 to .468
inch.--Translator's Note.) The second, the back one, contained
entirely within my packing-case, is closed at its far end and is 5 to 6
millimetres (.195 to.234 inch.--Translator's Note.) in diameter. Each of
the two parts of the double-galleried tunnel, one narrow and one wide,
measures at most a decimetre (3.9 inches.--Translator's Note.) in
length. I thought it advisable to have these short tubes, as the Osmia
is thus compelled to select different lodgings, each of them being
insufficient in itself to accommodate the total laying. In this way I
shall obtain a greater variety in the distribution of the sexes. Lastly,
at the mouth of each tube, which projects slightly outside the case,
there is a little paper tongue, forming a sort of perch on which the
Osmia alights on her arrival and giving easy access to the house. With
these facilities, the swarm colonized fifty-two double-galleried tubes,
thirty-seven cylindrical tubes, seventy-eight Snail-shells and a few old
nests of the Mason-bee of the Shrubs. From this rich mine of material I
will take what I want to prove my case.

Every series, even when incomplete, begins with females and ends with
males. To this rule I have not yet found an exception, at least in
galleries of normal diameter. In each new abode, the mother busies
herself first of all with the more important sex. Bearing this point
in mind, would it be possible for me, by manoeuvring, to obtain an
inversion of this order and make the laying begin with males? I
think so, from the results already ascertained and the irresistible
conclusions to be drawn from them. The double-galleried tubes are
installed in order to put my conjectures to the proof.

The back gallery, 5 or 6 millimetres (.195 to.234 inch.--Translator's
Note.) wide, is too narrow to serve as a lodging for normally developed
females. If, therefore, the Osmia, who is very economical of her space,
wishes to occupy them, she will be obliged to establish males there.
And her laying must necessarily begin here, because this corner is
the rear-most part of the tube. The foremost gallery is wide, with an
entrance-door on the front of the hive. Here, finding the conditions to
which she is accustomed, the mother will go on with her laying in the
order which she prefers.

Let us now see what has happened. Of the fifty-two double galleried
tubes, about a third did not have their narrow passage colonized. The
Osmia closed its aperture communicating with the large passage; and the
latter alone received the eggs. This waste of space was inevitable.
The female Osmiae, though nearly always larger than the males, present
marked differences among one another: some are bigger, some are smaller.
I had to adjust the width of the narrow galleries to Bees of average
dimensions. It may happen therefore that a gallery is too small to admit
the large-sized mothers to whom chance allots it. When the Osmia is
unable to enter the tube, obviously she will not colonize it. She then
closes the entrance to this space which she cannot use and does her
laying beyond it, in the wide tube. Had I tried to avoid these useless
apparatus by choosing tubes of larger calibre, I should have encountered
another drawback: the medium-sized mothers, finding themselves almost
comfortable, would have decided to lodge females there. I had to be
prepared for it: as each mother selected her house at will and as I was
unable to interfere in her choice, a narrow tube would be colonized or
not, according as the Osmia who owned it was or was not able to make her
way inside.

There remain some forty pairs of tubes with both galleries colonized. In
these there are two things to take into consideration. The narrow
rear tubes of 5 or 5 1/2 millimetres (.195 to.214 inch.--Translator's
Note.)--and these are the most numerous--contain males and males only,
but in short series, between one and five. The mother is here so much
hampered in her work that they are rarely occupied from end to end; the
Osmia seems in a hurry to leave them and to go and colonize the front
tube, whose ample space will leave her the liberty of movement necessary
for her operations. The other rear tubes, the minority, whose diameter
is about 6 millimetres (.234 inch.--Translator's Note.), contain
sometimes only females and sometimes females at the back and males
towards the opening. One can see that a tube a trifle wider and a mother
slightly smaller would account for this difference in the results.
Nevertheless, as the necessary space for a female is barely provided
in this case, we see that the mother avoids as far as she can a two-sex
arrangement beginning with males and that she adopts it only in the
last extremity. Finally, whatever the contents of the small tube may
be, those of the large one, following upon it, never vary and consist of
females at the back and males in front.

Though incomplete, because of circumstances very difficult to control,
the result of the experiment is none the less very striking. Twenty-five
apparatus contain only males in their narrow gallery, in numbers varying
from a minimum of one to a maximum of five. After these comes the colony
of the large gallery, beginning with females and ending with males. And
the layings in these apparatus do not always belong to late summer or
even to the intermediate period: a few small tubes contain the earliest
eggs of the Osmiae. A couple of Osmiae, more forward than the others,
set to work on the 23rd of April. Both of them started their laying by
placing males in the narrow tubes. The meagre supply of provisions was
enough in itself to show the sex, which proved later to be in accordance
with my anticipations. We see then that, by my artifices, the whole
swarm starts with the converse of the normal order. This inversion is
continued, at no matter what period, from the beginning to the end of
the operations. The series which, according to rule, would begin with
females now begins with males. Once the larger gallery is reached, the
laying is pursued in the usual order.

We have advanced one step and that no small one: we have seen that
the Osmia, when circumstances require it, is capable of reversing the
sequence of the sexes. Would it be possible, provided that the tube were
long enough, to obtain a complete inversion, in which the entire series
of the males should occupy the narrow gallery at the back and the entire
series of the females the roomy gallery in front? I think not; and I
will tell you why.

Long and narrow cylinders are by no means to the Osmia's taste, not
because of their narrowness but because of their length. Remember that
for each load of honey brought the worker is obliged to move backwards
twice. She enters, head first, to begin by disgorging the honey-syrup
from her crop. Unable to turn in a passage which she blocks entirely,
she goes out backwards, crawling rather than walking, a laborious
performance on the polished surface of the glass and a performance
which, with any other surface, would still be very awkward, as the wings
are bound to rub against the wall with their free end and are liable to
get rumpled or bent. She goes out backwards, reaches the outside, turns
round and goes in again, but this time the opposite way, so as to brush
off the load of pollen from her abdomen on to the heap. If the gallery
is at all long, this crawling backwards becomes troublesome after a
time; and the Osmia soon abandons a passage that is too small to allow
of free movement. I have said that the narrow tubes of my apparatus
are, for the most part, only very incompletely colonized. The Bee, after
lodging a small number of males in them, hastens to leave them. In the
wide front gallery, she can stay where she is and still be able to turn
round easily for her different manipulations; she will avoid those two
long journeys backwards, which are so exhausting and so bad for her
wings.

Another reason no doubt prompts her not to make too great a use of the
narrow passage, in which she would establish males, followed by females
in the part where the gallery widens. The males have to leave their
cells a couple of weeks or more before the females. If they occupy the
back of the house, they will die prisoners or else they will overturn
everything on their way out. This risk is avoided by the order which the
Osmia adopts.

In my tubes with their unusual arrangement, the mother might well find
the dilemma perplexing: there is the narrowness of the space at her
disposal and there is the emergence later on. In the narrow tubes, the
width is insufficient for the females; on the other hand, if she lodges
males there, they are liable to perish, since they will be prevented
from issuing at the proper moment. This would perhaps explain the
mother's hesitation and her obstinacy in settling females in some of my
apparatus which looked as if they could suit none but males.

A suspicion occurs to me, a suspicion aroused by my attentive
examination of the narrow tubes. All, whatever the number of their
inmates, are carefully plugged at the opening, just as separate tubes
would be. It might therefore be the case that the narrow gallery at the
back was looked upon by the Osmia not as the prolongation of the large
front gallery, but as an independent tube. The facility with which
the worker turns as soon as she reaches the wide tube, her liberty of
action, which is now as great as in a doorway communicating with the
outer air, might well be misleading and cause the Osmia to treat the
narrow passage at the back as though the wide passage in front did not
exist. This would account for the placing of the female in the large
tube above the males in the small tube, an arrangement contrary to her
custom.

I will not undertake to decide whether the mother really appreciates the
danger of my snares, or whether she makes a mistake in considering
only the space at her disposal and beginning with males. At any rate,
I perceive in her a tendency to deviate as little as possible from the
order which safeguards the emergence of the two sexes. This tendency is
demonstrated by her repugnance to colonizing my narrow tubes with long
series of males. However, so far as we are concerned, it does not matter
much what passes at such times in the Osmia's little brain. Enough for
us to know that she dislikes narrow and long tubes, not because they are
narrow, but because they are at the same time long.

And, in fact, she does very well with a short tube of the same diameter.
Such are the cells in the old nests of the Mason-bee of the Shrubs
and the empty shells of the Garden Snail. With the short tube, the two
disadvantages of the long tube are avoided. She has very little of that
crawling backwards to do when she has a Snail-shell for the home of
her eggs and scarcely any when the home is the cell of the Mason-bee.
Moreover, as the stack of cocoons numbers two or three at most, the
deliverance will be exempt from the difficulties attached to a long
series. To persuade the Osmia to nidify in a single tube long enough to
receive the whole of her laying and at the same time narrow enough
to leave her only just the possibility of admittance appears to me
a project without the slightest chance of success: the Bee would
stubbornly refuse such a dwelling or would content herself with
entrusting only a very small portion of her eggs to it. On the other
hand, with narrow but short cavities, success, without being easy,
seems to me at least quite possible. Guided by these considerations,
I embarked upon the most arduous part of my problem: to obtain the
complete or almost complete permutation of one sex with the other;
to produce a laying consisting only of males by offering the mother a
series of lodgings suited only to males.

Let us in the first place consult the old nests of the Mason-bee of the
Shrubs. I have said that these mortar spheroids, pierced all over
with little cylindrical cavities, are adopted pretty eagerly by the
Three-horned Osmia, who colonizes them before my eyes with females in
the deep cells and males in the shallow cells. That is how things go
when the old nest remains in its natural state. With a grater, however,
I scrape the outside of another nest so as to reduce the depth of
the cavities to some ten millimetres. (About two-fifths of an
inch.--Translator's Note.) This leaves in each cell just room for one
cocoon, surmounted by the closing stopper. Of the fourteen cavities in
the nests, I leave two intact, measuring fifteen millimetres in depth.
(.585 inch.--Translator's Note.) Nothing could be more striking than the
result of this experiment, made in the first year of my home rearing.
The twelve cavities whose depth had been reduced all received males; the
two cavities left untouched received females.

A year passes and I repeat the experiment with a nest of fifteen cells;
but this time all the cells are reduced to the minimum depth with the
grater. Well, the fifteen cells, from first to last, are occupied by
males. It must be quite understood that, in each case, all the offspring
belonged to one mother, marked with her distinguishing spot and kept
in sight as long as her laying lasted. He would indeed be difficult to
please who refused to bow before the results of these two experiments.
If, however, he is not yet convinced, here is something to remove his
last doubts.

The Three-horned Osmia often settles her family in old shells,
especially those of the Common Snail (Helix aspersa), who is so common
under the stone-heaps and in the crevices of the little unmortared walls
that support our terraces. In this species, the spiral is wide open, so
that the Osmia, penetrating as far down as the helical passage permits,
finds, immediately above the point which is too narrow to pass, the
space necessary for the cell of a female. This cell is succeeded by
others, wider still, always for females, arranged in a line in the same
way as in a straight tube. In the last whorl of the spiral, the diameter
would be too great for a single row. Then longitudinal partitions are
added to the transverse partitions, the whole resulting in cells of
unequal dimensions in which males predominate, mixed with a few females
in the lower storeys. The sequence of the sexes is therefore what it
would be in a straight tube and especially in a tube with a wide bore,
where the partitioning is complicated by subdivisions on the same level.
A single Snail-shell contains room for six or eight cells. A large,
rough earthen stopper finishes the nest at the entrance to the shell.

As a dwelling of this sort could show us nothing new, I chose for my
swarm the Garden Snail (Helix caespitum), whose shell, shaped like a
small, swollen Ammonite, widens by slow degrees, the diameter of the
usable portion, right up to the mouth, being hardly greater than that
required by a male Osmia-cocoon. Moreover, the widest part, in which
a female might find room, has to receive a thick stopping-plug, below
which there will often be a free space. Under all these conditions, the
house will hardly suit any but males arranged one after the other.

The collection of shells placed at the foot of each hive includes
specimens of different sizes. The smallest are 18 millimetres (.7
inch.--Translator's Note.) in diameter and the largest 24 millimetres
(.936 inch.--Translator's Note.) There is room for two cocoons, or three
at most, according to their dimensions.

Now these shells were used by my visitors without any hesitation,
perhaps even with more eagerness than the glass tubes, whose slippery
sides might easily be a little annoying to the Bee. Some of them were
occupied on the first few days of the laying; and the Osmia who
had started with a home of this sort would pass next to a second
Snail-shell, in the immediate neighbourhood of the first, to a third, a
fourth and others still, always close to one another, until her ovaries
were emptied. The whole family of one mother would thus be lodged in
Snail-shells which were duly marked with the date of the laying and a
description of the worker. The faithful adherents of the Snail-shell
were in the minority. The greater number left the tubes to come to
the shells and then went back from the shells to the tubes. All, after
filling the spiral staircase with two or three cells, closed the house
with a thick earthen stopper on a level with the opening. It was a long
and troublesome task, in which the Osmia displayed all her patience as
a mother and all her talents as a plasterer. There were even some who,
scrupulous to excess, carefully cemented the umbilicus, a hole which
seemed to inspire them with distrust as being able to give access to the
interior of the dwelling. It was a dangerous-looking cavity, which for
the greater safety of the family it was prudent to block up.

When the pupae are sufficiently matured, I proceed to examine
these elegant abodes. The contents fill me with joy: they fulfil my
anticipations to the letter. The great, the very great majority of the
cocoons turn out to be males; here and there, in the bigger cells, a
few rare females appear. The smallness of the space has almost done away
with the sixty-eight Snail-shells colonized. But, of this total number,
I must use only those series which received an entire laying and
were occupied by the same Osmia from the beginning to the end of
the egg-season. Here are a few examples, taken from among the most
conclusive.

From the 6th of May, when she started operations, to the 25th of
May, the date at which her laying ceased, the Osmia occupied seven
Snail-shells in succession. Her family consists of fourteen cocoons,
a number very near the average; and, of these fourteen cocoons, twelve
belong to males and only two to females. These occupy the seventh and
thirteenth places in chronological order.

Another, between the 9th and 27th of May, stocked six Snail-shells with
a family of thirteen, including ten males and three females. The places
occupied by the latter in the series were numbers 3, 4 and 5.

A third, between the 2nd and 29th of May, colonized eleven Snail-shells,
a prodigious task. This industrious one was also exceedingly prolific.
She supplied me with a family of twenty-six, the largest which I have
ever obtained from one Osmia. Well, this abnormal progeny consisted of
twenty-five males and one female, one alone, occupying place 17.

There is no need to go on, after this magnificent example, especially as
the other series would all, without exception, give us the same result.
Two facts are immediately obvious. The Osmia is able to reverse the
order of her laying and to start with a more or less long series of
males before producing any females. In the first case, the first female
appears as number 7; in the third, as number 17. There is something
better still; and this is the proposition which I was particularly
anxious to prove: the female sex can be permuted with the male sex and
can be permuted to the point of disappearing altogether. We see this
especially in the third case, where the presence of a solitary female
in a family of twenty-six is due to the somewhat larger diameter of the
corresponding Snail-shell and also, no doubt, to some mistake on the
mother's part, for the female cocoon, in a series of two, occupies the
upper storey, the one next to the orifice, an arrangement which the
Osmia appears to me to dislike.

This result throws so much light on one of the darkest corners of
biology that I must attempt to corroborate it by means of even more
conclusive experiments. I propose next year to give the Osmiae nothing
but Snail-shells for a lodging, picked out one by one, and rigorously
to deprive the swarm of any other retreat in which the laying could be
effected. Under these conditions, I ought to obtain nothing but males,
or nearly, for the whole swarm.

There would still remain the inverse permutation: to obtain only females
and no males, or very few. The first permutation makes the second seem
very probable, although I cannot as yet conceive a means of realizing
it. The only condition which I can regulate is the dimensions of the
home. When the rooms are small, the males abound and the females tend to
disappear. With generous quarters, the converse would not take place. I
should obtain females and afterwards an equal number of males, confined
in small cells which, in case of need, would be bounded by numerous
partitions. The factor of space does not enter into the question here.
What artifice can we then employ to provoke this second permutation? So
far, I can think of nothing that is worth attempting.

It is time to conclude. Leading a retired life, in the solitude of
a village, having quite enough to do with patiently and obscurely
ploughing my humble furrow, I know little about modern scientific views.
In my young days I had a passionate longing for books and found it
difficult to procure them; to-day, when I could almost have them if I
wanted, I am ceasing to wish for them. It is what usually happens as
life goes on. I do not therefore know what may have been done in the
direction whither this study of the sexes has led us. If I am stating
propositions that are really new or at least more comprehensive than the
propositions already known, my words will perhaps sound heretical. No
matter: as a simple translator of facts, I do not hesitate to make my
statement, being fully persuaded that time will turn my heresy into
orthodoxy. I will therefore recapitulate my conclusions.

Bees lay their eggs in series of first females and then males, when
the two sexes are of different sizes and demand an unequal quantity of
nourishment. When the two sexes are alike in size, the same sequence may
occur, but less regularly.

This dual arrangement disappears when the place chosen for the nest
is not large enough to contain the entire laying. We then see broken
layings, beginning with females and ending with males.

The egg, as it issues from the ovary, has not yet a fixed sex. The final
impress that produces the sex is given at the moment of laying or a
little before.

So as to be able to give each larva the amount of space and food that
suits it according as it is male or female, the mother can choose the
sex of the egg which she is about to lay. To meet the conditions of the
building, which is often the work of another or else a natural retreat
that admits of little or no alteration, she lays either a male egg or
a female egg as she pleases. The distribution of the sexes depends upon
herself. Should circumstances require it, the order of the laying can
be reversed and begin with males; lastly, the entire laying can contain
only one sex.

The same privilege is possessed by the predatory Hymenoptera, the Wasps,
at least by those in whom the two sexes are of a different size and
consequently require an amount of nourishment that is larger in the one
case than in the other. The mother must know the sex of the egg which
she is going to lay; she must be able to choose the sex of that egg so
that each larva may obtain its proper portion of food.

Generally speaking, when the sexes are of different sizes, every insect
that collects food and prepares or selects a dwelling for its offspring
must be able to choose the sex of the egg in order to satisfy without
mistake the conditions imposed upon it.

The question remains how this optional assessment of the sexes is
effected. I know absolutely nothing about it. If I should ever learn
anything about this delicate point, I shall owe it to some happy chance
for which I must wait, or rather watch, patiently. Towards the end of my
investigations, I heard of a German theory which relates to the Hive-bee
and comes from Dzierzon, the apiarist. (Johann Dzierzon, author of
"Theorie und Praxis des neuen Bienenfreundes."--Translator's Note.) If I
understand it aright, according to the very incomplete documents which I
have before me, the egg, as it issues from the ovary, is said already to
possess a sex, which is always the same; it is originally male; and it
becomes female by fertilization. The males are supposed to proceed from
non-fertilized eggs, the females from fertilized eggs. The Queen-bee
would thus lay female eggs or male eggs according as she fertilized them
or not while they were passing into her oviduct.

Coming from Germany, this theory cannot but inspire me with profound
distrust. As it has been given acceptance, with rash precipitancy, in
standard works, I will overcome my reluctance to devoting my attention
to Teutonic ideas and will submit it not to the test of argument, which
can always be met by an opposite argument, but to the unanswerable test
of facts.

For this optional fertilization, determining the sex, the mother's
organism requires a seminal reservoir which distils its drop of sperm
upon the egg contained in the oviduct and thus gives it a feminine
character, or else leaves it its original character, the male character,
by refusing it that baptism. This reservoir exists in the Hive-bee.
Do we find a similar organ in the other Hymenoptera, whether
honey-gatherers or hunters? The anatomical treatises are either silent
on this point or, without further enquiry, apply to the order as a whole
the data provided by the Hive-bee, however much she differs from the
mass of Hymenoptera owing to her social habits, her sterile workers and
especially her tremendous fertility, extending over so long a period.

I at first doubted the universal presence of this spermatic receptacle,
having failed to find it under my scalpel in my former investigations
into the anatomy of the Sphex-wasps and some other game-hunters. But
this organ is so delicate and so small that it very easily escapes the
eye, especially when our attention is not specially directed in search
of it; and, even when we are looking for it and it only, we do not
always succeed in discovering it. We have to find a globule attaining
in many cases hardly as much as a millimetre (About one-fiftieth of an
inch.--Translator's Note.) in diameter, a globule headed amidst a tangle
of air-ducts and fatty patches, of which it shares the colour, a dull
white. Then again, the merest slip of the forceps is enough to destroy
it. My first investigations, therefore, which concerned the reproductive
apparatus as a whole, might very well have allowed it to pass
unperceived.

In order to know the rights of the matter once and for all, as the
anatomical treatises taught me nothing, I once more fixed my microscope
on its stand and rearranged my old dissecting-tank, an ordinary tumbler
with a cork disk covered with black satin. This time, not without a
certain strain on my eyes, which are already growing tired, I succeeded
in finding the said organ in the Bembex-wasps, the Halicti (Cf.
Chapters 12 to 14 of the present volume.--Translator's Note.), the
Carpenter-bees, the Bumble-bees, the Andrenae (A species of Burrowing
Bees.--Translator's Note.) and the Megachiles. (Or Leaf-cutting Bees.
Cf. Chapter 8 of the present volume.--Translator's Note.) I failed in
the case of the Osmiae, the Chalicodomae and the Anthophorae. Is the
organ really absent? Or was there want of skill on my part? I
lean towards want of skill and admit that all the game-hunting and
honey-gathering Hymenoptera possess a seminal receptacle, which can be
recognized by its contents, a quantity of spiral spermatozoids whirling
and twisting on the slide of the microscope.

This organ once accepted, the German theory becomes applicable to all
the Bees and all the Wasps. When copulating, the female receives the
seminal fluid and holds it stored in her receptacle. From that moment,
the two procreating elements are present in the mother at one and the
same time: the female element, the ovule; and the male element, the
spermatozoid. At the egg-layer's will, the receptacle bestows a tiny
drop of its contents upon the matured ovule, when it reaches
the oviduct, and you have a female egg; or else it withholds its
spermatozoids and you have an egg that remains male, as it was at first.
I readily admit it: the theory is very simple, lucid and seductive. But
is it correct? That is another question.

One might begin by reproaching it with making a singular exception to
one of the most general rules. Which of us, casting his eyes over the
whole zoological progression, would dare to assert that the egg is
originally male and that it becomes female by fertilization? Do not the
two sexes both call for the assistance of the fertilizing element? If
there be one undoubted truth, it is certainly that. We are, it is true,
told very curious things about the Hive-bee. I will not discuss them:
this Bee stands too far outside the ordinary limits; and then the facts
asserted are far from being accepted by everybody. But the non-social
Bees and the predatory insects have nothing special about their laying.
Then why should they escape the common rule, which requires that every
living creature, male as well as female, should come from a fertilized
ovule? In its most solemn act, that of procreation, life is one and
uniform; what it does here it does there and there and everywhere. What!
The sporule of a scrap of moss requires an antherozoid before it is
fit to germinate; and the ovule of a Scolia, that proud huntress, can
dispense with the equivalent in order to hatch and produce a male? These
new-fangled theories seem to me to have very little value.

One might also bring forward the case of the Three-pronged Osmia, who
distributes the two sexes without any order in the hollow of her reed.
What singular whim is the mother obeying when, without decisive motive,
she opens her seminal phial at haphazard to anoint a female egg, or
else keeps it closed, also at haphazard, to allow a male egg to pass
unfertilized? I could imagine impregnation being given or withheld
for periods of some duration; but I cannot understand impregnation and
non-impregnation following upon each other anyhow, in any sort of order,
or rather with no order it all. The mother has just fertilized an egg.
Why should she refuse to fertilize the next, when neither the provisions
nor the lodgings differ in the smallest respect from the previous
provisions and lodgings? These capricious alternations, so unreasonable
and so exceedingly erratic, are scarcely appropriate to an act of such
importance.

But I promised not to argue and I find myself arguing. My reasoning is
too fine for dull wits. I will pass on and come to the brutal fact, the
real sledge-hammer blow.

Towards the end of the Bee's operations, in the first week of June, the
last acts of the Three-horned Osmia become so exceptionally interesting
that I made her the object of redoubled observation. The swarm at this
time is greatly reduced in numbers. I have still some thirty laggards,
who continue very busy, though their work is in vain. I see some very
conscientiously stopping up the entrance to a tube or a Snail-shell in
which they have laid nothing at all. Others are closing the home after
only building a few partitions, or even mere attempts at partitions.
Some are placing at the back of a new gallery a pinch of pollen which
will benefit nobody and then shutting up the house with an earthen
stopper as thick, as carefully made as though the safety of a family
depended on it. Born a worker, the Osmia must die working. When her
ovaries are exhausted, she spends the remainder of her strength on
useless works: partitions, plugs, pollen-heaps, all destined to be left
unemployed. The little animal machine cannot bring itself to be inactive
even when there is nothing more to be done. It goes on working so that
its last vibrations of energy may be used up in fruitless labour. I
commend these aberrations to the staunch supporters of reasoning-powers
in the animal.

Before coming to these useless tasks, my laggards have laid their last
eggs, of which I know the exact cells, the exact dates. These eggs, as
far as the microscopes can tell, differ in no respect from the others,
the older ones. They have the same dimensions, the same shape, the same
glossiness, the same look of freshness. Nor are their provisions in
any way peculiar, being very well suited to the males, who conclude the
laying. And yet these last eggs do not hatch: they wrinkle, fade and
wither on the pile of food. In one case, I count three or four sterile
eggs among the last lot laid; in another, I find two or only one.
Elsewhere in the swarm, fertile eggs have been laid right up to the end.

Those sterile eggs, stricken with death at the moment of their birth,
are too numerous to be ignored. Why do they not hatch like the other
eggs, which outwardly they resemble in every respect? They have received
the same attention from the mother and the same portion of food. The
searching microscope shows me nothing in them to explain the fatal
ending.

To the unprejudiced mind, the answer is obvious. Those eggs do not hatch
because they have not been fertilized. Any animal or vegetable egg that
had not received the life-giving impregnation would perish in the same
way. No other answer is possible. It is no use talking of the distant
period of the laying: eggs of the same period laid by other mothers,
eggs of the same date and likewise the final ones of a laying, are
perfectly fertile. Once more, they do not hatch because they were not
fertilized.

And why were they not fertilized? Because the seminal receptacle, so
tiny, so difficult to see that it sometimes escaped me despite all
my scrutiny, had exhausted its contents. The mothers in whom this
receptacle retained a remnant of sperm to the end had their last eggs as
fertile as the first; the others, whose seminal reservoir was exhausted
too soon, had their last-born stricken with death. All this seems to me
as clear as daylight.

If the unfertilized eggs perish without hatching, those which hatch and
produce males are therefore fertilized; and the German theory falls to
the ground.

Then what explanation shall I give of the wonderful facts which I have
set forth? Why, none, absolutely none. I do not explain facts, I relate
them. Growing daily more sceptical of the interpretations suggested to
me and more hesitating as to those which I may have to suggest myself,
the more I observe and experiment, the more clearly I see rising out of
the black mists of possibility an enormous note of interrogation.

Dear insects, my study of you has sustained me and continues to sustain
me in my heaviest trials. I must take leave of you for to-day. The ranks
are thinning around me and the long hopes have fled. Shall I be able to
speak to you again? (This is the closing paragraph of Volume 3 of the
"Souvenirs entomologiques," of which the author has lived to publish
seven more volumes, containing over 2,500 pages and nearly 850,000
words.--Translator's Note.)




CHAPTER 6. INSTINCT AND DISCERNMENT.

The Pelopaeus (A Mason-wasp forming the subject of essays which have not
yet been published in English.--Translator's Note.) gives us a very poor
idea of her intellect when she plasters up the spot in the wall where
the nest which I have removed used to stand, when she persists in
cramming her cell with Spiders for the benefit of an egg no longer there
and when she dutifully closes a cell which my forceps has left
empty, extracting alike germ and provisions. The Mason-bees (Cf. "The
Mason-bees": chapter 7.--Translator's Note.), the caterpillar of the
Great Peacock Moth (Cf. "Social Life in the Insect World" by J.H. Fabre,
translated by Bernard Miall: chapter 14.--Translator's Note.) and
many others, when subjected to similar tests, are guilty of the same
illogical behaviour: they continue, in the normal order, their series
of industrious actions, though an accident has now rendered them all
useless. Just like millstones unable to cease revolving though there be
no corn left to grind, let them once be given the compelling power and
they will continue to perform their task despite its futility. Are they
then machines? Far be it from me to think anything so foolish.

It is impossible to make definite progress on the shifting sands
of contradictory facts: each step in our interpretation may find us
embogged. And yet these facts speak so loudly that I do not hesitate
to translate their evidence as I understand it. In insect mentality, we
have to distinguish two very different domains. One of these is INSTINCT
properly so called, the unconscious impulse that presides over the
most wonderful part of what the creature achieves. Where experience and
imitation are of absolutely no avail, instinct lays down its inflexible
law. It is instinct and instinct alone that makes the mother build for a
family which she will never see; that counsels the storing of
provisions for the unknown offspring; that directs the sting towards the
nerve-centres of the prey and skilfully paralyses it, so that the game
may keep good; that instigates, in fine, a host of actions wherein
shrewd reason and consummate science would have their part, were the
creature acting through discernment.

This faculty is perfect of its kind from the outset, otherwise the
insect would have no posterity. Time adds nothing to it and takes
nothing from it. Such as it was for a definite species, such it is
to-day and such it will remain, perhaps the most settled zoological
characteristic of them all. It is not free nor conscious in its
practice, any more than is the faculty of the stomach for digestion
or that of the heart for pulsation. The phases of its operations are
predetermined, necessarily entailed one by another; they suggest a
system of clock-work wherein one wheel set in motion brings about the
movement of the next. This is the mechanical side of the insect,
the fatum, the only thing which is able to explain the monstrous
illogicality of a Pelopaeus when misled by my artifices. Is the Lamb
when it first grips the teat a free and conscious agent, capable of
improvement in its difficult art of taking nourishment? The insect is no
more capable of improvement in its art, more difficult still, of giving
nourishment.

But, with its hide-bound science ignorant of itself, pure insect, if it
stood alone, would leave the insect unarmed in the perpetual conflict
of circumstances. No two moments in time are identical; though the
background remain the same, the details change; the unexpected rises on
every side. In this bewildering confusion, a guide is needed to seek,
accept, refuse and select; to show preference for this and indifference
to that; to turn to account, in short, anything useful that occasion may
offer. This guide the insect undoubtedly possesses, to a very manifest
degree. It is the second province of its mentality. Here it is conscious
and capable of improvement by experience. I dare not speak of this
rudimentary faculty as intelligence, which is too exalted a title: I
will call it DISCERNMENT. The insect, in exercising its highest gifts,
discerns, differentiates between one thing and another, within the
sphere of its business, of course; and that is about all.

As long as we confound acts of pure instinct and acts of discernment
under the same head, we shall fall back into those endless discussions
which embitter controversy without bringing us one step nearer to the
solution of the problem. Is the insect conscious of what it does? Yes
and no. No, if its action is in the province of instinct; yes, if the
action is in that of discernment. Are the habits of an insect capable of
modification? No, decidedly not, if the habit in question belongs to the
province of instinct; yes, if it belongs to that of discernment. Let us
state this fundamental distinction more precisely by the aid of a few
examples.

The Pelopaeus builds her cells with earth already softened, with mud.
Here we have instinct, the unalterable characteristic of the worker.
She has always built in this way and always will. The passing ages will
never teach her, neither the struggle for life nor the law of selection
will ever induce her to imitate the Mason-bee and collect dry dust
for her mortar. This mud nest needs a shelter against the rain. The
hiding-place under a stone suffices at first. But should she find
something better, the potter takes possession of that something better
and instals herself in the home of man. (The Pelopaeus builds in the
fire-places of houses.--Translator's Note.) There we have discernment,
the source of some sort of capacity for improvement.

The Pelopaeus supplies her larvae with provisions in the form of
Spiders. There you have instinct. The climate, the longitude or
latitude, the changing seasons, the abundance or scarcity of game
introduce no modification into this diet, though the larva shows itself
satisfied with other fare provided by myself. Its forebears were brought
up on Spiders; their descendants consumed similar food; and their
posterity again will know no other. Not a single circumstance, however
favourable, will ever persuade the Pelopaeus that young Crickets, for
instance, are as good as Spiders and that her family would accept them
gladly. Instinct binds her down to the national diet.

But, should the Epeira (The Weaving or Garden Spider. Cf. "The Life
of the Spider" by J. Henri Fabre translated by Alexander Teixeira
de Mattos; chapters 9 to 14 and appendix.--Translator's Note.), the
favourite prey, be lacking, must the Pelopaeus therefore give up
foraging? She will stock her warehouses all the same, because any Spider
suits her. There you have discernment, whose elasticity makes up, in
certain circumstances, for the too-great rigidity of instinct. Amid the
innumerable variety of game, the huntress is able to discern between
what is Spider and what is not; and, in this way, she is always prepared
to supply her family, without quitting the domain of her instinct.

The Hairy Ammophila gives her larva a single caterpillar, a large one,
paralysed by as many pricks of her sting as it has nervous centres in
its thorax and abdomen. Her surgical skill in subduing the monster is
instinct displayed in a form which makes short work of any inclination
to see in it an acquired habit. In an art that can leave no one to
practise it in the future unless that one be perfect at the outset, of
what avail are happy chances, atavistic tendencies, the mellowing hand
of time? But the grey caterpillar, sacrificed one day, may be succeeded
on another day by a green, yellow or striped caterpillar. There you have
discernment, which is quite capable of recognizing the regulation prey
under very diverse garbs.

The Megachiles build their honey-jars with disks cut out of leaves;
certain Anthidia make felted cotton wallets; others fashion pots out
of resin. There you have instinct. Will any rash mind ever conceive the
singular idea that the Leaf-cutter might very well have started working
in cotton, that the cotton-wool-worker once thought or will one
day think of cutting disks out of the leaves of the lilac- and the
rose-tree, that the resin-kneader began with clay? Who would dare to
indulge in any such theories? Each Bee has her art, her medium, to which
she strictly confines herself. The first has her leaves; the second
her wadding; the third her resin. None of these guilds has ever changed
trades with another; and none ever will. There you have instinct,
keeping the workers to their specialities. There are no innovations
in their workshops, no recipes resulting from experiment, no ingenious
devices, no progress from indifferent to good, from good to excellent.
To-day's method is the facsimile of yesterday's; and to-morrow will know
no other.

But, though the manufacturing-process is invariable, the raw material is
subject to change. The plant that supplies the cotton differs in species
according to the locality; the bush out of whose leaves the pieces will
be cut is not the same in the various fields of operation; the tree that
provides the resinous putty may be a pine, a cypress, a juniper, a
cedar or a spruce, all very different in appearance. What will guide the
insect in its gleaning? Discernment.

These, I think, are sufficient details of the fundamental distinction
to be drawn in the insect's mentality; the distinction, that is, between
instinct and discernment. If people confuse these two provinces, as they
nearly always do, any understanding becomes impossible; the last glimmer
of light disappears behind the clouds of interminable discussions. From
an industrial point of view, let us look upon the insect as a worker
thoroughly versed from birth in a craft whose essential principles never
vary; let us grant that unconscious worker a gleam of intelligence
which will permit it to extricate itself from the inevitable conflict of
attendant circumstances; and I think that we shall have come as near to
the truth as the state of our knowledge will allow for the moment.

Having thus assigned a due share both to instinct and the aberrations
of instinct when the course of its different phases is disturbed, let
us see what discernment is able to do in the selection of a site for
the nest and materials for building it; and, leaving the Pelopaeus, upon
whom it is useless to dwell any longer, let us consider other examples,
picked from among those richest in variations.

The Mason-bee of the Sheds (Chalicodoma rufitarsis, PEREZ) well deserves
the name which I have felt justified in giving her from her habits: she
settles in numerous colonies in our sheds, on the lower surface of the
tiles, where she builds huge nests which endanger the solidity of the
roof. Nowhere does the insect display a greater zeal for work than in
one of these colossal cities, an estate which is constantly increasing
as it passes down from one generation to another; nowhere does it find a
better workshop for the exercise of its industry. Here it has plenty of
room: a quiet resting-place, sheltered from damp and from excess of heat
or cold.

But the spacious domain under the tiles is not within the reach of all:
sheds with free access and the proper sunny aspect are pretty rare.
These sites fall only to the favoured of fortune. Where will the others
take up their quarters? More or less everywhere. Without leaving the
house in which I live, I can enumerate stone, wood, glass, metal, paint
and mortar as forming the foundation of the nests. The green-house with
its furnace heat in the summer and its bright light, equalling that
outside, is fairly well-frequented. The Mason-bee hardly ever fails to
build there each year, in squads of a few dozen apiece, now on the glass
panes, now on the iron bars of the framework. Other little swarms settle
in the window embrasures, under the projecting ledge of the front door
or in the cranny between the wall and an open shutter. Others again,
being perhaps of a morose disposition, flee society and prefer to work
in solitude, one in the inside of a lock or of a pipe intended to carry
the rain-water from the leads; another in the mouldings of the doors and
windows or in the crude ornamentation of the stone-work. In short,
the house is made use of all round, provided that the shelter be an
out-of-door one; for observe that the enterprising invader, unlike
the Pelopaeus, never penetrates inside our dwellings. The case of
the conservatory is an exception more apparent than real: the glass
building, standing wide open throughout the summer, is to the Mason-bee
but a shed a little lighter than the others. There is nothing here to
arouse the distrust with which anything indoors or shut up inspires
her. To build on the threshold of an outer door, or to usurp its lock,
a hiding-place to her fancy, is all that she allows herself; to go any
farther is an adventure repugnant to her taste.

Lastly, in the case of all these dwellings, the Mason-bee is man's free
tenant; her industry makes use of the products of our own industry. Can
she have no other establishments? She has, beyond a doubt; she possesses
some constructed on the ancient plan. On a stone the size of a man's
fist, protected by the shelter of a hedge, sometimes even on a pebble
in the open air, I see her building now groups of cells as large as a
walnut, now domes emulating in size, shape and solidity those of her
rival, the Mason-bee of the Walls.

The stone support is the most frequent, though not the only one. I have
found nests, but sparsely inhabited it is true, on the trunks of trees,
in the seams of the rough bark of oaks. Among those whose support was
a living plant, I will mention two that stand out above all the others.
The first was built in the lobe of a torch-thistle as thick as my leg;
the second rested on a stalk of the opuntia, the Indian fig. Had the
fierce armour of these two stout cactuses attracted the attention of the
insect, which looked upon their tufts of spikes as furnishing a system
of defence for its nest? Perhaps so. In any case, the attempt was not
imitated; I never saw another installation of the kind. There is one
definite conclusion to be drawn from my two discoveries. Despite the
oddity of their structure, which is unparalleled among the local flora,
the two American importations did not compel the insect to go through an
apprenticeship of groping and hesitation. The one which found itself in
the presence of those novel growths, and which was perhaps the first of
its race to do so, took possession of their lobes and stalks just as it
would have done of a familiar site. From the start, the fleshy plants
from the New World suited it as well as the trunk of a native tree.

The Mason-bee of the Pebbles (Chalicodoma parietina) has none of this
elasticity in the choice of a site. In her case, the smooth stone of the
parched uplands is the almost invariable foundation of her structures.
Elsewhere, under a less clement sky, she prefers the support of a
wall, which protects the nest against the prolonged snows. Lastly, the
Mason-bee of the Shrubs (Chalicodoma rufescens, PEREZ) fixes her ball of
clay to a twig of any ligneous plant, from the thyme, the rock-rose and
the heath to the oak, the elm and the pine. The list of the sites that
suit her would almost form a complete catalogue of the ligneous flora.

The variety of places wherein the insect instals itself, so eloquent of
the part played by discernment in their selection, becomes still more
remarkable when it is accompanied by a corresponding variety in the
architecture of the cells. This is more particularly the case with
the Three-horned Osmia, who, as she uses clayey materials very easily
affected by the rain, requires, like the Pelopaeus, a dry shelter for
her cells, a shelter which she finds ready-made and uses just as it is,
after a few touches by way of sweeping and cleansing. The homes which I
see her adopt are especially the shells of Snails that have died under
the stone-heaps and in the low, unmortared walls which support the
cultivated earth of the hills in shelves or terraces. The use of
Snail-shells is accompanied by the no less active use of the old cells
of both the Mason-bee of the Sheds and of certain Anthophorae (A.
pilipes, A. parietina and A. personata).

We must not forget the reed, which is highly appreciated when--a rare
find--it appears under the requisite conditions. In its natural state,
the plant with the mighty hollow cylinders is of no possible use to the
Osmia, who knows nothing of the art of perforating a woody wall. The
gallery of an internode has to be wide open before the insect can
take possession of it. Also, the clean-cut stump must be horizontal,
otherwise the rain would soften the fragile edifice of clay and soon lay
it low; also, the stump must not be lying on the ground and must be kept
at some distance from the dampness of the soil. We see therefore that,
without the intervention of man, involuntary in the vast majority of
cases and deliberate only on the experimenter's part, the Osmia would
hardly ever find a reed-stump suited to the installation of her family.
It is to her a casual acquisition, a home unknown to her race before
men took it into their heads to cut reeds and make them into hurdles for
drying figs in the sun.

How did the work of man's pruning-knife bring about the abandonment of
the natural lodging? How was the spiral staircase of the Snail-shell
replaced by the cylindrical gallery of the reed? Was the change from one
kind of house to another effected by gradual transitions, by attempts
made, abandoned, resumed, becoming more and more definite in their
results as generation succeeded generation? Or did the Osmia, finding
the cut reed that answered her requirements, instal herself there
straightway, scorning her ancient dwelling, the Snail-shell? These
questions called for a reply; and they have received one. Let us
describe how things happened.

Near Serignan are some great quarries of coarse limestone,
characteristic of the miocene formation of the Rhone valley. These
have been worked for many generations. The ancient public buildings of
Orange, notably the colossal frontage of the theatre whither all the
intellectual world once flocked to hear Sophocles' "Oedipus Tyrannus,"
derive most of their material from these quarries. Other evidence
confirms what the similarity of the hewn stone tells us. Among the
rubbish that fills up the spaces between the tiers of seats, they
occasionally discover the Marseilles obol, a bit of silver stamped
with the four-spoked wheel, or a few bronze coins bearing the effigy of
Augustus or Tiberius. Scattered also here and there among the monuments
of antiquity are heaps of refuse, accumulations of broken stones
in which various Hymenoptera, including the Three-horned Osmia in
particular, take possession of the dead Snail-shell.

The quarries form part of an extensive plateau which is so arid as to be
nearly deserted. In these conditions, the Osmia, at all times faithful
to her birth-place, has little or no need to emigrate from her heap of
stones and leave the shell for another dwelling which she would have
to go and seek at a distance. Since there are heaps of stone there, she
probably has no other dwelling than the Snail-shell. Nothing tells us
that the present-day generations are not descended in the direct line
from the generations contemporary with the quarryman who lost his as or
his obol at this spot. All the circumstances seem to point to it: the
Osmia of the quarries is an inveterate user of Snail-shells; so far as
heredity is concerned, she knows nothing whatever of reeds. Well, we
must place her in the presence of these new lodgings.

I collect during the winter about two dozen well-stocked Snail-shells
and instal them in a quiet corner of my study, as I did at the time of
my enquiries into the distribution of the sexes. The little hive with
its front pierced with forty holes has bits of reed fitted to it. At the
foot of the five rows of cylinders I place the inhabited shells and
with these I mix a few small stones, the better to imitate the natural
conditions. I add an assortment of empty Snail-shells, after carefully
cleaning the interior so as to make the Osmia's stay more pleasant. When
the time comes for nest-building, the stay-at-home insect will have,
close beside the house of its birth, a choice of two habitations: the
cylinder, a novelty unknown to its race; and the spiral staircase, the
ancient ancestral home.

The nests were finished at the end of May and the Osmiae began to answer
my list of questions. Some, the great majority, settled exclusively
in the reeds; the others remained faithful to the Snail-shell or else
entrusted their eggs partly to the spirals and partly to the cylinders.
With the first, who were the pioneers of cylindrical architecture, there
was no hesitation that I could perceive: after exploring the stump of
reed for a time and recognizing it as serviceable, the insect
instals itself there and, an expert from the first touch, without
apprenticeship, without groping, without any tendencies bequeathed by
the long practice of its predecessors, builds its straight row of cells
on a very different plan from that demanded by the spiral cavity of the
shell which increases in size as it goes on.

The slow school of the ages, the gradual acquisitions of the past,
the legacies of heredity count for nothing therefore in the Osmia's
education. Without any novitiate on its own part or that of its
forebears, the insect is versed straight away in the calling which it
has to pursue; it possesses, inseparable from its nature, the qualities
demanded by its craft: some which are invariable and belong to the
domain of instinct; others, flexible, belonging to the province of
discernment. To divide a free lodging into chambers by means of mud
partitions; to fill those chambers with a heap of pollen-flour, with a
few sups of honey in the central part where the egg is to lie; in short,
to prepare board and lodging for the unknown, for a family which the
mothers have never seen in the past and will never see in the future:
this, in its essential features, is the function of the Osmia's
instinct. Here, everything is harmoniously, inflexibly, permanently
preordained; the insect has but to follow its blind impulse to attain
the goal. But the free lodging offered by chance varies exceedingly in
hygienic conditions, in shape and in capacity. Instinct, which does
not choose, which does not contrive, would, if it were alone, leave
the insect's existence in peril. To help her out of her predicament,
in these complex circumstances, the Osmia possesses her little stock of
discernment, which distinguishes between the dry and the wet, the solid
and the fragile, the sheltered and the exposed; which recognizes the
worth or the worthlessness of a site and knows how to sprinkle it with
cells according to the size and shape of the space at disposal. Here,
slight industrial variations are necessary and inevitable; and the
insect excels in them without any apprenticeship, as the experiment with
the native Osmia of the quarries has just proved.

Animal resources have a certain elasticity, within narrow limits. What
we learn from the animals' industry at a given moment is not always the
full measure of their skill. They possess latent powers held in reserve
for certain emergencies. Long generations can succeed one another
without employing them; but, should some circumstance require it,
suddenly those powers burst forth, free of any previous attempts,
even as the spark potentially contained in the flint flashes forth
independently of all preceding gleams. Could one who knew nothing of the
Sparrow but her nest under the eaves suspect the ball-shaped nest at the
top of a tree? Would one who knew nothing of the Osmia save her home
in the Snail-shell expect to see her accept as her dwelling a stump
of reed, a paper funnel, a glass tube? My neighbour the Sparrow,
impulsively taking it into her head to leave the roof for the
plane-tree, the Osmia of the quarries, rejecting her natal cabin, the
spiral of the shell, for my cylinder, alike show us how sudden and
spontaneous are the industrial variations of animals.




CHAPTER 7. ECONOMY OF ENERGY.

What stimulus does the insect obey when it employs the reserve powers
that slumber in its race? Of what use are its industrial variations? The
Osmia will yield us her secret with no great difficulty. Let us examine
her work in a cylindrical habitation. I have described in full detail,
in the foregoing pages, the structure of her nests when the dwelling
adopted is a reed-stump or any other cylinder; and I will content myself
here with recapitulating the essential features of that nest-building.

We must first distinguish three classes of reeds according to their
diameter: the small, the medium-sized and the large. I call small those
whose narrow width just allows the Osmia to go about her household
duties without discomfort. She must be able to turn where she stands
in order to brush her abdomen and rub off its load of pollen, after
disgorging the honey in the centre of the heap of flour already
collected. If the width of the tube does not admit of this operation,
if the insect is obliged to go out and then come in again backwards in
order to place itself in a favourable posture for the discharge of the
pollen, then the reed is too narrow and the Osmia is rather reluctant
to accept it. The middle-sized reeds and a fortiori the large ones leave
the victualler entire liberty of action; but the former do not exceed
the width of a cell, a width agreeing with the bulk of the future
cocoon, whereas the latter, with their excessive diameter, require more
than one chamber on the same floor.

When free to choose, the Osmia settles by preference in the small reeds.
Here, the work of building is reduced to its simplest expression and
consists in dividing the tube by means of earthen partitions into a
straight row of cells. Against the partition forming the back wall of
the preceding cell the mother places first a heap of honey and pollen;
next, when the portion is seen to be enough, she lays an egg in the
centre of it. Then and then only she resumes her plasterer's work
and marks out the length of the new cell with a mud partition. This
partition in its turn serves as the rear-wall of another chamber, which
is first victualled and then closed; and so on until the cylinder is
sufficiently colonized and receives a thick terminal stopper at
its orifice. In a word, the chief characteristic of this method of
nest-building, the roughest of all, is that the partition in front is
not undertaken so long as the victualling is still incomplete, or, in
other words, that the provisions and the egg are deposited before the
Bee sets to work on the partition.

At first sight, this latter detail hardly deserves attention: is it
not right to fill the pot before we put a lid on? The Osmia who owns a
medium-sized reed is not at all of this opinion; and other plasterers
share her views, as we shall see when we watch the Odynerus building
her nest. (A genus of Mason-wasps, the essays on which have not yet been
translated into English.--Translator's Note.) Here we have an excellent
illustration of one of those latent powers held in reserve for
exceptional occasions and suddenly brought into play, although often
very far removed from the insect's regular methods. If the reed, without
being of inordinate width from the point of view of the cocoon, is
nevertheless too spacious to afford the Bee a suitable purchase against
the wall at the moment when she is disgorging honey and brushing off her
load of pollen; the Osmia altogether changes the order of her work; she
sets up the partition first and then does the victualling.

All round the inside of the tube she places a ring of mud, which, as the
result of her constant visits to the mortar, ends by becoming a complete
diaphragm minus an orifice at the side, a sort of round dog-hole, just
large enough for the insect to pass through. When the cell is thus
marked out and almost wholly closed, the Osmia attends to the storing of
her provisions and the laying of her eggs. Steadying herself against the
margin of the hole at one time with her fore-legs and at another with
her hind-legs, she is able to empty her crop and to brush her abdomen;
by pressing against it, she obtains a foothold for her little efforts
in these various operations. When the tube was narrow, the outer wall
supplied this foothold and the earthen partition was postponed until the
heap of provisions was completed and surmounted by the egg; but in
the present case the passage is too wide and would leave the insect
floundering helplessly in space, so the partition with its serving-hatch
takes precedence of the victuals. This method is a little more expensive
than the other, first in materials, because of the diameter of the reed,
and secondly in time, if only because of the dog-hole, a delicate piece
of mortar-work which is too soft at first and cannot be used until it
has dried and become harder. Therefore the Osmia, who is sparing of her
time and strength, accepts medium-sized reeds only when there are no
small ones available.

The large tubes she will use only in grave emergencies and I am unable
to state exactly what these exceptional circumstances are. Perhaps she
decides to make use of those roomy dwellings when the eggs have to be
laid at once and there is no other shelter in the neighbourhood. While
my cylinder-hives gave me plenty of well-filled reeds of the first and
second class, they provided me with but half-a-dozen at most of the
third, notwithstanding my precaution to furnish the apparatus with a
varied assortment.

The Osmia's repugnance to big cylinders is quite justified. The work in
fact is longer and more costly when the tubes are wide. An inspection of
a nest constructed under these conditions is enough to convince us. It
now consists not of a string of chambers obtained by simple transverse
partitions, but of a confused heap of clumsy, many-sided compartments,
standing back to back, with a tendency to group themselves in storeys
without succeeding in doing so, because any regular arrangement would
mean that the ceilings possessed a span which it is not in the builder's
power to achieve. The edifice is not a geometrical masterpiece and it
is even less satisfactory from the point of view of economy. In the
previous constructions, the sides of the reed supplied the greater part
of the walls and the work was limited to one partition for each cell.
Here, except at the actual periphery, where the tube itself supplies a
foundation, everything has to be obtained by sheer building: the floor,
the ceiling, the walls of the many-sided compartment are one and all
made of mortar. The structure is almost as costly in materials as that
of the Chalicodoma or the Pelopaeus.

It must be pretty difficult, too, when one thinks of its irregularity.
Fitting as best she can the projecting angles of the new cell into the
recessed corners of the cell already built, the Osmia runs up walls
more or less curved, upright or slanting, which intersect one another at
various points, so that each compartment requires a new and
complicated plan of construction, which is very different from the
circular-partition style of architecture, with its row of parallel
dividing-disks. Moreover, in this composite arrangement, the size of the
recesses left available by the earlier work to some extent decides
the assessment of the sexes, for, according to the dimensions of those
recesses, the walls erected take in now a larger space, the home of
a female, and now a smaller space, the home of a male. Roomy quarters
therefore have a double drawback for the Osmia: they greatly increase
the outlay in materials; and also they establish in the lower layers,
among the females, males who, because of their earlier hatching, would
be much better placed near the mouth of the nest. I am convinced of it:
if the Osmia refuses big reeds and accepts them only in the last resort,
when there are no others, it is because she objects to additional labour
and to the mixture of the sexes.

The Snail-shell, then, is but an indifferent home for her, which she
is quite ready to abandon should a better offer. Its expanding cavity
represents an average between the favourite small cylinder and the
unpopular large cylinder, which is accepted only when there is no other
obtainable. The first whorls of the spiral are too narrow to be of use
to the Osmia, but the middle ones have the right diameter for cocoons
arranged in single file. Here things happen as in a first-class reed,
for the helical curve in no way affects the method of structure employed
for a rectilinear series of cells. Circular partitions are erected at
the required distances, with or without a serving-hatch, according to
the diameter. These mark out the first cells, one after the other, which
are reserved solely for the females. Then comes the last whorl, which
is much too wide for a single row of cells; and here we once more find,
exactly as in a wide reed, a costly profusion of masonry, an irregular
arrangement of the cells and a mixture of the sexes.

Having said so much, let us go back to the Osmia of the quarries. Why,
when I offer them simultaneously Snail-shells and reeds of a suitable
size, do the old frequenters of the shells prefer the reeds, which in
all probability have never before been utilized by their race? Most of
them scorn the ancestral dwelling and enthusiastically accept my reeds.
Some, it is true, take up their quarters in the Snail-shell; but even
among these a goodly number refuse my new shells and return to their
birth-place, the old Snail-shell, in order to utilize the family
property, without much labour, at the cost of a few repairs. Whence,
I ask, comes this general preference for the cylinder, never used
hitherto? The answer can be only this: of two lodgings at her disposal
the Osmia selects the one that provides a comfortable home at a minimum
outlay. She economizes her strength when restoring an old nest; she
economizes it when replacing the Snail-shell by the reed.

Can animal industry, like our own, obey the law of economy, the sovran
law that governs our industrial machine even as it governs, at least to
all appearances, the sublime machine of the universe? Let us go
deeper into the question and bring other workers into evidence, those
especially who, better equipped perhaps and at any rate better fitted
for hard work, attack the difficulties of their trade boldly and look
down upon alien establishments with scorn. Of this number are the
Chalicodomae, the Mason-bees proper.

The Mason-bee of the Pebbles does not make up her mind to build a
brand-new dome unless there be a dearth of old and not quite dilapidated
nests. The mothers, sisters apparently and heirs-at-law to the domain,
dispute fiercely for the ancestral abode. The first who, by sheer brute
force, takes possession of the dome, perches upon it and, for long
hours, watches events while polishing her wings. If some claimant puts
in an appearance, forthwith the other turns her out with a volley of
blows. In this way the old nests are employed so long as they have not
become uninhabitable hovels.

Without being equally jealous of the maternal inheritance, the Mason-bee
of the Sheds eagerly uses the cells whence her generation issued. The
work in the huge city under the eaves begins thus: the old cells,
of which, by the way, the good-natured owner yields a portion to
Latreille's Osmia and to the Three-horned Osmia alike, are first made
clean and wholesome and cleared of broken plaster and then provisioned
and shut. When all the accessible chambers are occupied, the actual
building begins with a new stratum of cells upon the former edifice,
which becomes more and more massive from year to year.

The Mason-bee of the Shrubs, with her spherical nests hardly larger than
walnuts, puzzled me at first. Does she use the old buildings or does she
abandon them for good? To-day perplexity makes way for certainty: she
uses them very readily. I have several times surprised her lodging
her family in the empty rooms of a nest where she was doubtless born
herself. Like her kinswoman of the Pebbles, she returns to the native
dwelling and fights for its possession. Also, like the dome-builder,
she is an anchorite and prefers to cultivate the lean inheritance alone.
Sometimes, however, the nest is of exceptional size and harbours a crowd
of occupants, who live in peace, each attending to her business, as in
the colossal hives in the sheds. Should the colony be at all numerous
and the estate descend to two or three generations in succession, with a
fresh layer of masonry each year, the normal walnut-sized nest becomes
a ball as large as a man's two fists. I have gathered on a pine-tree
a nest of the Mason-bee of the Shrubs that weighed a kilogram (2.205
pounds avoirdupois.--Translator's Note.) and was the size of a child's
head. A twig hardly thicker than a straw served as its support. The
casual sight of that lump swinging over the spot on which I had sat down
made me think of the mishap that befell Garo. (The hero of La Fontaine's
fable, "Le Gland et la Citrouille," who wondered why acorns grew on such
tall trees and pumpkins on such low vines, until he fell asleep under
one of the latter and a pumpkin dropped upon his nose.--Translator's
Note.) If such nests were plentiful in the trees, any one seeking the
shade would run a serious risk of having his head smashed.

After the Masons, the Carpenters. Among the guild of wood-workers, the
most powerful is the Carpenter-bee (Xylocopa violacea (Cf. "The Life
of the Spider": chapter 1.--Translator's Note.)), a very large Bee of
formidable appearance, clad in black velvet with violet-coloured wings.
The mother gives her larvae as a dwelling a cylindrical gallery which
she digs in rotten wood. Useless timber lying exposed to the air,
vine-poles, large logs of fire-wood seasoning out of doors, heaped up
in front of the farmhouse porch, stumps of trees, vine-stocks and big
branches of all kinds are her favourite building-yards. A solitary and
industrious worker, she bores, bit by bit, circular passages the width
of one's thumb, as clear-cut as though they were made with an auger.
A heap of saw-dust accumulates on the ground and bears witness to the
severity of the task. Usually, the same aperture is the entrance to
two or three parallel corridors. With several galleries there is
accommodation for the entire laying, though each gallery is quite
short; and the Bee thus avoids those long series which always create
difficulties when the moment of hatching arrives. The laggards and the
insects eager to emerge are less likely to get in each other's way.

After obtaining the dwelling, the Carpenter-bee behaves like the Osmia
who is in possession of a reed. Provisions are collected, the egg is
laid and the chamber is walled in front with a saw-dust partition. The
work is pursued in this way until the two or three passages composing
the house are completely stocked. Heaping up provisions and erecting
partitions are an invariable feature of the Xylocopa's programme; no
circumstance can release the mother from the duty of providing for the
future of her family, in the matter both of ready-prepared food and of
separate compartments for the rearing of each larva. It is only in
the boring of the galleries, the most laborious part of the work, that
economy can occasionally be exercised by a piece of luck. Well, is the
powerful Carpenter, all unheeding of fatigue, able to take advantage of
such fortunate occasions? Does she know how to make use of houses which
she has not tunnelled herself? Why, yes: a free lodging suits her just
as much as it does the various Mason-bees. She knows as well as they the
economic advantages of an old nest that is still in good condition: she
settles down, as far as possible, in her predecessors' galleries, after
freshening up the sides with a superficial scraping. And she does better
still. She readily accepts lodgings which have never known a drill, no
matter whose. The stout reeds used in the trellis-work that supports the
vines are valuable discoveries, providing as they do sumptuous galleries
free of cost. No preliminary work or next to none is required with
these. Indeed, the insect does not even trouble to make a side-opening,
which would enable it to occupy the cavity contained within two nodes;
it prefers the opening at the end cut by man's pruning-knife. If the
next partition be too near to give a chamber of sufficient length, the
Xylocopa destroys it, which is easy work, not to be compared with the
labour of cutting an entrance through the side. In this way, a spacious
gallery, following on the short vestibule made by the pruning-knife, is
obtained with the least possible expenditure of energy.

Guided by what was happening on the trellises, I offered the black Bee
the hospitality of my reed-hives. From the very beginning, the insect
gladly welcomed my advances; each spring, I see it inspect my rows of
cylinders, pick out the best ones and instal itself there. Its work,
reduced to a minimum by my intervention, is limited to the partitions,
the materials for which are obtained by scraping the inner sides of the
reed.

As first-rate joiners, next to the Carpenter-bees come the Lithurgi,
of whom my district possesses two species: L. cornutus, FAB., and L.
chrysurus, BOY. By what aberration of nomenclature was the name of
Lithurgus, a worker in stone, given to insects which work solely
in wood? I have caught the first, the stronger of the two, digging
galleries in a large block of oak that served as an arch for a
stable-door; I have always found the second, who is more widely
distributed, settling in dead wood--mulberry, cherry, almond,
poplar--that was still standing. Her work is exactly the same as the
Xylocopa's, on a smaller scale. A single entrance-hole gives access
to three or four parallel galleries, assembled in a serried group;
and these galleries are subdivided into cells by means of saw-dust
partitions. Following the example of the big Carpenter-bee, Lithurgus
chrysurus knows how to avoid the laborious work of boring, when occasion
offers: I find her cocoons lodged almost as often in old dormitories
as in new ones. She too has the tendency to economize her strength by
turning the work of her predecessors to account. I do not despair of
seeing her adopt the reed if, one day, when I possess a large enough
colony, I decide to try this experiment on her. I will say nothing about
L. cornutus, whom I only once surprised at her carpentering.

The Anthophorae, those children of the precipitous earthy banks, show
the same thrifty spirit as the other members of the mining corporation.
Three species, A. parietina, A. personata and A. pilipes, dig long
corridors leading to the cells, which are scattered here and there and
one by one. These passages remain open at all seasons of the year. When
spring comes, the new colony uses them just as they are, provided
that they are well preserved in the clayey mass baked by the sun; it
increases their length if necessary, runs out a few more branches, but
does not decide to start boring in new ground until the old city, which,
with its many labyrinths, resembles some monstrous sponge, is too much
undermined for safety. The oval niches, the cells that open on those
corridors, are also profitably employed. The Anthophora restores their
entrance, which has been destroyed by the insect's recent emergence;
she smooths their walls with a fresh coat of whitewash, after which the
lodging is fit to receive the heap of honey and the egg. When the old
cells, insufficient in number and moreover partly inhabited by diverse
intruders, are all occupied, the boring of new cells begins, in the
extended sections of the galleries, and the rest of the eggs are housed.
In this way, the swarm is settled at a minimum of expense.

To conclude this brief account, let us change the zoological setting
and, as we have already spoken of the Sparrow, see what he can do as a
builder. The simplest form of his nest is the great round ball of straw,
dead leaves and feathers, in the fork of a few branches. It is costly in
material, but can be set up anywhere, when the hole in the wall or the
shelter of a tile are lacking. What reasons induced him to give up the
spherical edifice? To all seeming, the same reasons that led the
Osmia to abandon the Snail-shell's spiral, which requires a fatiguing
expenditure of clay, in favour of the economical cylinder of the reed.
By making his home in a hole in the wall, the Sparrow escapes the
greater part of his work. Here, the dome that serves as a protection
from the rain and the thick walls that offer resistance to the wind both
become superfluous. A mere mattress is sufficient; the cavity in the
wall provides the rest. The saving is great; and the Sparrow appreciates
it quite as much as the Osmia.

This does not mean that the primitive art has disappeared, lost through
neglect; it remains an ineffaceable characteristic of the species, ever
ready to declare itself should circumstances demand it. The generations
of to-day are as much endowed with it as the generations of yore;
without apprenticeship, without the example of others, they have within
themselves, in the potential state, the industrial aptitude of their
ancestors. If aroused by the stimulus of necessity, this aptitude will
pass suddenly from inaction to action. When, therefore, the Sparrow
still from time to time indulges in spherical building, this is not
progress on his part, as is sometimes contended; it is, on the contrary,
a retrogression, a return to the ancient customs, so prodigal of labour.
He is behaving like the Osmia who, in default of a reed, makes shift
with a Snail-shell, which is more difficult to utilize but easier to
find. The cylinder and the hole in the wall stand for progress; the
spiral of the Snail-shell and the ball-shaped nest represent the
starting-point.

I have, I think, sufficiently illustrated the inference which is borne
out by the whole mass of analogous facts. Animal industry manifests a
tendency to achieve the essential with a minimum of expenditure; after
its own fashion, the insect bears witness to the economy of energy. On
the one hand, instinct imposes upon it a craft that is unchangeable
in its fundamental features; on the other hand, it is left a certain
latitude in the details, so as to take advantage of favourable
circumstances and attain the object aimed at with the least possible
expenditure of time, materials and work, the three elements of
mechanical labour. The problem in higher geometry solved by the Hive-bee
is only a particular case--true, a magnificent case,--of this general
law of economy which seems to govern the whole animal world. The wax
cells, with their maximum capacity as against a minimum wall-space, are
the equivalent, with the superaddition of a marvellous scientific skill,
of the Osmia's compartments in which the stonework is reduced to a
minimum through the selection of a reed. The artificer in mud and the
artificer in wax obey the same tendency: they economize. Do they know
what they are doing? Who would venture to suggest it in the case of
the Bee grappling with her transcendental problem? The others,
pursuing their rustic art, are no wiser. With all of them, there is no
calculation, no premeditation, but simply blind obedience to the law of
general harmony.




CHAPTER 8. THE LEAF-CUTTERS.

It is not enough that animal industry should be able, to a certain
extent, to adapt itself to casual exigencies when choosing the site of
a nest; if the race is to thrive, something else is required, something
which hide-bound instinct is unable to provide. The Chaffinch, for
instance, introduces a great quantity of lichen into the outer layer of
his nest. This is his method of strengthening the edifice and making
a stout framework in which to place first the bottom mattress of moss,
fine straw and rootlets and then the soft bed of feathers, wool and
down. But, should the time-honoured lichen be lacking, will the bird
refrain from building its nest? Will it forgo the delight of hatching
its brood because it has not the wherewithal to settle its family in the
orthodox fashion?

No, the chaffinch is not perplexed by so small a matter; he is an expert
in materials, he understands botanical equivalents. In the absence of
the branches of the evernias, he picks the long beards of the usneas,
the wartlike rosettes of the parmelias, the membranes of the stictises
torn away in shreds; if he can find nothing better, he makes shift with
the bushy tufts of the cladonias. As a practical lichenologist, when one
species is rare or lacking in the neighbourhood, he is able to fall back
on others, varying greatly in shape, colour and texture. And, if the
impossible happened and lichen failed entirely, I credit the Chaffinch
with sufficient talent to be able to dispense with it and to build the
foundations of his nest with some coarse moss or other.

What the worker in lichens tells us the other weavers of textile
materials confirm. Each has his favourite flora, which hardly ever
varies when the plant is easily accessible and which can be supplemented
by plenty of others when it is not. The bird's botany would be worth
examining; it would be interesting to draw up the industrial herbal of
each species. In this connection, I will quote just one instance, so as
not to stray too far from the subject in hand.

The Red-backed Shrike (Lanius collurio), the commonest variety in my
district, is noteworthy because of his savage mania for forked gibbets,
the thorns in the hedgerows whereon he impales the voluminous contents
of his game-bag--little half-fledged birds, small Lizards, Grasshoppers,
caterpillars, Beetles--and leaves them to get high. To this passion for
the gallows, which has passed unnoticed by the country-folk, at least
in my part, he adds another, an innocent botanical passion, which is
so much in evidence that everybody, down to the youngest bird's-nester,
knows all about it. His nest, a massive structure, is made of hardly
any other materials than a greyish and very fluffy plant, which is
found everywhere among the corn. This is the Filago spathulata of the
botanists; and the bird also makes use, though less frequently, of the
Filago germanica, or common cotton-rose. Both are known in Provencal by
the name herbo dou tarnagas, or Shrike-herb. This popular designation
tells us plainly how faithful the bird is to its plant. To have struck
the agricultural labourer, a very indifferent observer, the Shrike's
choice of materials must be remarkably persistent.

Have we here a taste that is exclusive? Not in the least. Though
cotton-roses of all species are plentiful on level ground, they become
scarce and impossible to find on the parched hills. The bird, on its
side, is not given to journeys of exploration and takes what it finds to
suit it in the neighbourhood of its tree or hedge. But on arid ground,
the Micropus erectus, or upright micropus, abounds and is a satisfactory
substitute for the Filago so far as its tiny, cottony leaves and its
little fluffy balls of flowers are concerned. True, it is short and
does not lend itself well to weaver's work. A few long sprigs of another
cottony plant, the Helichrysum staechas, or wild everlasting, inserted
here and there, will give body to the structure. Thus does the Shrike
manage when hard up for his favourite materials: keeping to the same
botanical family, he is able to find and employ substitutes among the
fine cotton-clad stalks.

He is even able to leave the family of the Compositae and to go gleaning
more or less everywhere. Here is the result of my botanizings at the
expense of his nests. We must distinguish between two genera in the
Shrike's rough classification: the cottony plants and the smooth plants.
Among the first, my notes mention the following: Convolvulus cantabrica,
or flax-leaved bindweed; Lotus symmetricus, or bird's-foot trefoil;
Teucrium polium, or poly; and the flowery heads of the Phragmites
communis, or common reed. Among the second are these: Medicago lupulina,
or nonesuch; Trifolium repens, or white clover; Lathyrus pratensis, or
meadow lathyrus; Capsella bursa pastoris, or shepherd's purse; Vicia
peregrina, or broad-podded vetch; Convolvulus arvensis, or small
bindweed; Pterotheca nemausensis, a sort of hawkweed; and Poa pratensis,
or smooth-stalked meadow-grass. When it is downy, the plant forms almost
the whole nest, as is the case with the flax-leaved bindweed; when
smooth, it forms only the framework, destined to support a crumbling
mass of micropus, as is the case with the small bindweed. When making
this collection, which I am far from giving as the birds' complete
herbarium, I was struck by a wholly unexpected detail: of the various
plants, I found only the heads still in bud; moreover, all the sprigs,
though dry, possessed the green colouring of the growing plant, a sign
of swift desiccation in the sun. Save in a few cases, therefore, the
Shrike does not collect the dead and withered remains: it is from the
growing plants that he reaps his harvest, mowing them down with his beak
and leaving the sheaves to dry in the sun before using them. I caught
him one day hopping about and pecking at the twigs of a Biscayan
bindweed. He was getting in his hay, strewing the ground with it.

The evidence of the Shrike, confirmed by that of all the other
workers--weavers, basket-makers or woodcutters--whom we may care to call
as witnesses, shows us what a large part must be assigned to discernment
in the bird's choice of materials for its nest. Is the insect as highly
gifted? When it works with vegetable matter, is it exclusive in its
tastes? Does it know only one definite plant, its special province? Or
has it, for employment in its manufactures, a varied flora, in which its
discernment exercises a free choice? For answers to these questions we
may look, above all, to the Leaf-cutting Bees, the Megachiles. Reaumur
has told the story of their industry in detail; and I refer the reader
who wishes for further particulars to the master's Memoirs.

The man who knows how to use his eyes in his garden will observe, some
day or other, a number of curious holes in the leaves of his lilac- and
rose-trees, some of them round, some oval, as if idle but skilful
hands had been at work with the pinking-iron. In some places, there is
scarcely anything but the veins of the leaves left. The author of the
mischief is a grey-clad Bee, a Megachile. For scissors, she has her
mandibles; for compasses, producing now an oval and anon a circle, she
has her eye and the pivot of her body. The pieces cut out are made into
thimble-shaped wallets, destined to contain the honey and the egg:
the larger, oval pieces supply the floor and sides; the smaller, round
pieces are reserved for the lid. A row of these thimbles, placed one on
top of the other, up to a dozen or more, though often there are less:
that is, roughly, the structure of the Leaf-cutter's nest.

When taken out of the recess in which the mother has manufactured it,
the cylinder of cells seems to be an indivisible whole, a sort of tunnel
obtained by lining with leaves some gallery dug underground. The real
thing does not correspond with its appearance: under the least pressure
of the fingers, the cylinder breaks up into equal sections, which are so
many compartments independent of their neighbours as regards both floor
and lid. This spontaneous break up shows us how the work is done. The
method agrees with those adopted by the other Bees. Instead of a
general scabbard of leaves, afterwards subdivided into compartments by
transverse partitions, the Megachile constructs a string of separate
wallets, each of which is finished before the next is begun.

A structure of this sort needs a sheath to keep the pieces in place
while giving them the proper shape. The bag of leaves, in fact, as
turned out by the worker, lacks stability; its numerous pieces, not
glued together, but simply placed one after the other, come apart and
give way as soon as they lose the support of the tunnel that keeps them
united. Later, when it spins its cocoon, the larva infuses a little
of its fluid silk into the gaps and solders the pieces to one another,
especially the inner ones, so much so that the insecure bag in due
course becomes a solid casket whose component parts it is no longer
possible to separate entirely.

The protective sheath, which is also a framework, is not the work of
the mother. Like the great majority of the Osmiae, the Megachiles do not
understand the art of making themselves a home straight away: they
want a borrowed lodging, which may vary considerably in character.
The deserted galleries of the Anthophorae, the burrows of the fat
Earth-worms, the tunnels bored in the trunks of trees by the larva of
the Cerambyx-beetle (The Capricorn, the essay on which has not yet been
published in English.--Translator's Note.), the ruined dwellings of
the Mason-bee of the Pebbles, the Snail-shell nests of the Three-horned
Osmia, reed-stumps, when these are handy, and crevices in the walls
are all so many homes for the Leaf-cutters, who choose this or that
establishment according to the tastes of their particular genus.

For the sake of clearness, let us cease generalizing and direct our
attention to a definite species. I first selected the White-girdled
Leaf-cutter (Megachile albocincta, PEREZ), not on account of any
exceptional peculiarities, but solely because this is the Bee most
often mentioned in my notes. Her customary dwelling is the tunnel of an
Earth-worm opening on some clay bank. Whether perpendicular or slanting,
this tunnel runs down to an indefinite depth, where the climate would be
too damp for the Bee. Besides, when the time comes for the hatching of
the adult insect, its emergence would be fraught with peril if it had
to climb up from a deep pit through crumbling rubbish. The Leaf-cutter,
therefore, uses only the front portion of the Worm's gallery, two
decimetres at most. (7.8 inches.--Translator's Note.) What is to be done
with the rest of the tunnel? It is an ascending shaft, tempting to an
enemy; and some underground ravager might come this way and destroy the
nest by attacking the row of cells at the back.

The danger is foreseen. Before fashioning her first honey-bag, the
Bee blocks the passage with a strong barricade composed of the only
materials used in the Leaf-cutter's guild. Fragments of leaves are
piled up in no particular order, but in sufficient quantities to make
a serious obstacle. It is not unusual to find in the leafy rampart some
dozens of pieces rolled into screws and fitting into one another like
a stack of cylindrical wafers. For this work of fortification, artistic
refinement seems superfluous; at any rate, the pieces of leaves are for
the most part irregular. You can see that the insect has cut them out
hurriedly, unmethodically and on a different pattern from that of the
pieces intended for the cells.

I am struck with another detail in the barricade. Its constituents
are taken from stout, thick, strong-veined leaves. I recognize young
vine-leaves, pale-coloured and velvety; the leaves of the whitish
rock-rose (Cistus albidus), lined with a hairy felt; those of the
holm-oak, selected among the young and bristly ones; those of the
hawthorn, smooth but tough; those of the cultivated reed, the only one
of the Monocotyledones exploited, as far as I know, by the Megachiles.
In the construction of cells, on the other hand, I see smooth leaves
predominating, notably those of the wild briar and of the common acacia,
the robinia. It would appear, therefore, that the insect distinguishes
between two kinds of materials, without being an absolute purist and
sternly excluding any sort of blending. The very much indented leaves,
whose projections can be completely removed with a dexterous snip of
the scissors, generally furnish the various layers of the barricade; the
little robinia-leaves, with their fine texture and their unbroken edges,
are better suited to the more delicate work of the cells.

A rampart at the back of the Earth-worm's shaft is a wise precaution and
the Leaf-cutter deserves all credit for it; only it is a pity for the
Megachiles' reputation that this protective barrier often protects
nothing at all. Here we see, under a new guise, that aberration of
instinct of which I gave some examples in an earlier chapter. My notes
contain memoranda of various galleries crammed with pieces of leaves
right up to the orifice, which is on a level with the ground, and
entirely devoid of cells, even of an unfinished one. These were
ridiculous fortifications, of no use whatever; and yet the Bee treated
the matter with the utmost seriousness and took infinite pains over her
futile task. One of these uselessly barricaded galleries furnished me
with some hundred pieces of leaves arranged like a stack of wafers;
another gave me as many as a hundred and fifty. For the defence of a
tenanted nest, two dozen and even fewer are ample. Then what was the
object of the Leaf-cutter's ridiculous pile?

I wish I could believe that, seeing that the place was dangerous, she
made her heap bigger so that the rampart might be in proportion to
the danger. Then, perhaps, at the moment of starting on the cells, she
disappeared, the victim of an accident, blown out of her course by
a gust of wind. But this line of defence is not admissible in the
Megachile's case. The proof is palpable: the galleries aforesaid are
barricaded up to the level of the ground; there is no room, absolutely
none, to lodge even a single egg. What was her object, I ask again, when
she persisted in obstinately piling up her wafers? Has she really an
object?

I do not hesitate to say no. And my answer is based upon what the Osmiae
taught me. I have described above how the Three-horned Osmia, towards
the end of her life, when her ovaries are depleted, expends on useless
operations such energy as remains to her. Born a worker, she is bored by
the inactivity of retirement; her leisure requires an occupation. Having
nothing better to do, she sets up partitions; she divides a tunnel
into cells that will remain empty; she closes with a thick plug reeds
containing nothing. Thus is the modicum of strength of her decline
exhausted in vain labours. The other Builder-bees behave likewise. I see
Anthidia laboriously provide numerous bales of cotton to stop galleries
wherein never an egg was laid; I see Mason-bees build and then
religiously close cells that will remain unvictualled and uncolonized.

The long and useless barricades then belong to the last hours of the
Megachile's life, when the eggs are all laid; the mother, whose ovaries
are exhausted, persists in building. Her instinct is to cut out and heap
up pieces of leaves; obeying this impulse, she cuts out and heaps up
even when the supreme reason for this labour ceases. The eggs are no
longer there, but some strength remains; and that strength is expended
as the safety of the species demanded in the beginning. The wheels of
action go on turning in the absence of the motives for action; they
continue their movement as though by a sort of acquired velocity. What
clearer proof can we hope to find of the unconsciousness of the animal
stimulated by instinct?

Let us return to the Leaf-cutter's work under normal conditions.
Immediately after a protective barrier comes the row of cells, which
vary considerably in number, like those of the Osmia in her reed.
Strings of about a dozen are rare; the most frequent consist of five or
six. No less subject to variation is the number of pieces joined to make
a cell: pieces of two kinds, some, the oval ones, forming the honey-pot;
others, the round ones, serving as a lid. I count, on an average, eight
to ten pieces of the first kind. Though all cut on the pattern of an
ellipse, they are not equal in dimensions and come under two categories.
The larger, outside ones are each of them almost a third of the
circumference and overlap one another slightly. Their lower end bends
into a concave curve to form the bottom of the bag. Those inside, which
are considerably smaller, increase the thickness of the sides and fill
up the gaps left by the first.

The Leaf-cutter therefore is able to use her scissors according to the
task before her: first, the large pieces, which help the work forward,
but leave empty spaces; next, the small pieces, which fit into the
defective portions. The bottom of the cell particularly comes in for
after-touches. As the natural curve of the larger pieces is not enough
to provide a cup without cracks in it, the Bee does not fail to improve
the work with two or three small oval pieces applied to the imperfect
joins.

Another advantage results from the snippets of unequal size. The three
or four outer pieces, which are the first placed in position, being
the longest of all, project beyond the mouth, whereas the next, being
shorter, do not come quite up to it. A brim is thus obtained, a ledge
on which the round disks of the lid rest and are prevented from touching
the honey when the Bee presses them into a concave cover. In other
words, at the mouth the circumference comprises only one row of leaves;
lower down it takes two or three, thus restricting the diameter and
securing an hermetic closing.

The cover of the pot consists solely of round pieces, very nearly alike
and more or less numerous. Sometimes I find only two, sometimes I count
as many as ten, closely stacked. At times, the diameter of these pieces
is of an almost mathematical precision, so much so that the edges of the
disk rest upon the ledge. No better result would be obtained had they
been cut out with the aid of compasses. At times, again, the piece
projects slightly beyond the mouth, so that, to enter, it has to be
pressed down and curved cupwise. There is no variation in the diameter
of the first pieces placed in position, those nearest to the honey.
They are all of the same size and thus form a flat cover which does not
encroach on the cell and will not afterwards interfere with the larva,
as a convex ceiling would. The subsequent disks, when the pile is
numerous, are a little larger; they only fit the mouth by yielding to
pressure and becoming concave. The Bee seems to make a point of this
concavity, for it serves as a mould to receive the curved bottom of the
next cell.

When the row of cells is finished, the task still remains of blocking up
the entrance to the gallery with a safety-stopper similar to the earthen
plug with which the Osmia closes her reeds. The Bee then returns to the
free and easy use of the scissors which we noticed at the beginning when
she was fencing off the back part of the Earth-worm's too deep burrow;
she cuts out of the foliage irregular pieces of different shapes and
sizes and often retaining their original deeply-indented margins; and
with all these pieces, very few of which fit at all closely the orifice
to be blocked, she succeeds in making an inviolable door, thanks to the
huge number of layers.

Let us leave the Leaf-cutter to finish depositing her eggs in other
galleries, which will be colonized in the same manner, and consider for
a moment her skill as a cutter. Her edifices consist of a multitude of
fragments belonging to three categories: oval pieces for the sides
of the cells; round pieces for the lids; and irregular pieces for the
barricades at the front and back. The last present no difficulty: the
Bee obtains them by removing from the leaf some projecting portion,
as it stands, a serrate lobe which, owing to its notches, shortens the
insect's task and lends itself better to scissor-work. So far, there
is nothing to deserve attention: it is unskilled labour, in which an
inexperienced apprentice might excel.

With the oval pieces, it becomes another matter. What model has the
Megachile when cutting her neat ellipses out of the delicate material
for her wallets, the robinia-leaves? What mental pattern guides her
scissors? What system of measurement tells her the dimensions? One would
like to picture the insect as a living pair of compasses, capable of
tracing an elliptic curve by a certain natural inflexion of its body,
even as our arm traces a circle by swinging from the shoulder. A
blind mechanism, the mere outcome of its organization, would alone be
responsible for its geometry. This explanation would tempt me if the
large oval pieces were not accompanied by much smaller ones, also oval,
which are used to fill the empty spaces. A pair of compasses which
changes its radius of its own accord and alters the curve according to
the plan before it appears to me an instrument somewhat difficult to
believe in. There must be something better than that. The circular
pieces of the lid suggest it to us.

If, by the mere flexion inherent in her structure, the Leaf-cutter
succeeds in cutting out ovals, how does she succeed in cutting out
rounds? Can we admit the presence of other wheels in the machinery for
the new pattern, so different in shape and size? Besides, the real point
of the difficulty does not lie there. These rounds, for the most part,
fit the mouth of the jar with almost exact precision. When the cell
is finished, the Bee flies hundreds of yards away to make the lid. She
arrives at the leaf from which the disk is to be cut. What picture, what
recollection has she of the pot to be covered? Why, none at all: she has
never seen it; she does her work underground, in utter darkness! At the
utmost, she can have the indications of touch: not actual indications,
of course, for the pot is not there, but past indications, useless in
a work of precision. And yet the disk to be cut out must have a fixed
diameter: if it were too large, it would not go in; if too small, it
would close badly, it would slip down on the honey and suffocate the
egg. How shall it be given its correct dimensions without a pattern? The
Bee does not hesitate for a moment. She cuts out her disk with the same
celerity which she would display in detaching any shapeless lobe that
might do for a stopper; and that disk, without further measurement, is
of the right size to fit the pot. Let whoso will explain this geometry,
which in my opinion is inexplicable, even when we allow for memory
begotten of touch and sight.

One winter evening, as we were sitting round the fire, whose cheerful
blaze unloosed our tongues, I put the problem of the Leaf-cutter to my
family:

'Among your kitchen-utensils,' I said, 'you have a pot in daily use;
but it has lost its lid, which was knocked over and broken by the Tomcat
playing among the shelves. To-morrow is market-day and one of you will
be going to Orange to buy the week's provisions. Would she undertake,
without a measure of any kind, with the sole aid of memory, which we
would allow her to refresh before starting by a careful examination of
the object, to bring back exactly what the pot wants, a lid neither too
large nor too small, in short the same size as the top?'

It was admitted with one accord that nobody would accept such a
commission without taking a measure with her, or at least a bit of
string giving the width. Our memory for sizes is not accurate enough.
She would come back from the town with something that 'might do'; and it
would be the merest chance if this turned out to be the right size.

Well, the Leaf-cutter is even less well-off than ourselves. She has no
mental picture of her pot, because she has never seen it; she is not
able to pick and choose in the crockery-dealer's heap, which acts as
something of a guide to our memory by comparison; she must, without
hesitation, far away from her home, cut out a disk that fits the top of
her jar. What is impossible to us is child's-play to her. Where we could
not do without a measure of some kind, a bit of string, a pattern or
a scrap of paper with figures upon it, the little Bee needs nothing at
all. In housekeeping matters she is cleverer than we are.

One objection was raised. Was it not possible that the Bee, when at work
on the shrub, should first cut a round piece of an approximate diameter,
larger than that of the neck of the jar, and that afterwards, on
returning home, she should gnaw away the superfluous part until the lid
exactly fitted the pot? These alterations made with the model in front
of her would explain everything.

That is perfectly true; but are there any alterations? To begin with, it
seems to me hardly possible that the insect can go back to the cutting
once the piece is detached from the leaf: it lacks the necessary support
to gnaw the flimsy disk with any precision. A tailor would spoil his
cloth if he had not the support of a table when cutting out the pieces
for a coat. The Megachile's scissors, so difficult to wield on anything
not firmly held, would do equally bad work.

Besides, I have better evidence than this for my refusal to believe in
the existence of alterations when the Bee has the cell in front of her.
The lid is composed of a pile of disks whose number sometimes reaches
half a score. Now the bottom part of all these disks is the under
surface of the leaf, which is paler and more strongly veined; the top
part is the upper surface, which is smooth and greener. In other words,
the insect places them in the position which they occupy when gathered.
Let me explain. In order to cut out a piece, the Bee stands on the
upper surface of the leaf. The piece detached is held in the feet and
is therefore laid with its top surface against the insect's chest at the
moment of departure. There is no possibility of its being turned over on
the journey. Consequently, the piece is laid as the Bee has just picked
it, with the lower surface towards the inside of the cell and the upper
surface towards the outside. If alterations were necessary to reduce the
lid to the diameter of the pot, the disk would be bound to get turned
over: the piece, manipulated, set upright, turned round, tried this way
and that, would, when finally laid in position, have its top or bottom
surface inside just as it happened to come. But this is exactly what
does not take place. Therefore, as the order of stacking never changes,
the disks are cut, from the first clip of the scissors, with their
proper dimensions. The insect excels us in practical geometry. I look
upon the Leaf-cutter's pot and lid as an addition to the many other
marvels of instinct that cannot be explained by mechanics; I submit it
to the consideration of science; and I pass on.

The Silky Leaf-cutter (Megachile sericans, FONSCOL.; M. Dufourii, LEP.)
makes her nests in the disused galleries of the Anthophorae. I know
her to occupy another dwelling which is more elegant and affords a more
roomy installation: I mean the old dwelling of the fat Capricorn, the
denizen of the oaks. The metamorphosis is effected in a spacious chamber
lined with soft felt. When the long-horned Beetle reaches the adult
stage, he releases himself and emerges from the tree by following a
vestibule which the larva's powerful tools have prepared beforehand.
When the deserted cabin, owing to its position, remains wholesome and
there is no sign of any running from its walls, no brown stuff smelling
of the tan-yard, it is soon visited by the Silky Megachile, who finds in
it the most sumptuous of the apartments inhabited by the Leaf-cutters.
It combines every condition of comfort: perfect safety, an even
temperature, freedom from damp, ample room; and so the mother who is
fortunate enough to become the possessor of such a lodging uses it
entirely, vestibule and drawing-room alike. Accommodation is found for
all her family of eggs; at least, I have nowhere seen nests as populous
as here.

One of them provides me with seventeen cells, the highest number
appearing in my census of the Megachile clan. Most of them are lodged in
the nymphal chamber of the Capricorn; and, as the spacious recess is too
wide for a single row, the cells are arranged in three parallel series.
The remainder, in a single string, occupy the vestibule, which is
completed and filled up by the terminal barricade. In the materials
employed, hawthorn-and paliurus-leaves predominate. The pieces, both
in the cells and in the barrier, vary in size. It is true that the
hawthorn-leaves, with their deep indentations, do not lend themselves to
the cutting of neat oval pieces. The insect seems to have detached each
morsel without troubling overmuch about the shape of the piece, so long
as it was big enough. Nor has it been very particular about arranging
the pieces according to the nature of the leaf: after a few bits of
paliurus come bits of vine and hawthorn; and these again are followed by
bits of bramble and paliurus. The Bee has collected her pieces anyhow,
taking a bit here and there, just as her fancy dictated. Nevertheless,
paliurus is the commonest, perhaps for economical reasons.

I notice, in fact, that the leaves of this shrub, instead of being
used piecemeal, are employed whole, when they do not exceed the proper
dimensions. Their oval form and their moderate size suit the insect's
requirements; and there is therefore no necessity to cut them into
pieces. The leaf-stalk is clipped with the scissors and, without more
ado, the Megachile retires the richer by a first-rate bit of material.

Split up into their component parts, two cells give me altogether
eighty-three pieces of leaves, whereof eighteen are smaller than the
others and of a round shape. The last-named come from the lids. If they
average forty-two each, the seventeen cells of the nest represent seven
hundred and fourteen pieces. These are not all: the nest ends, in the
Capricorn's vestibule, with a stout barricade in which I count three
hundred and fifty pieces. The total therefore amounts to one thousand
and sixty-four. All those journeys and all that work with the scissors
to furnish the deserted chamber of the Cerambyx! If I did not know the
Leaf-cutter's solitary and jealous disposition, I should attribute the
huge structure to the collaboration of several mothers; but there is
no question of communism in this case. One dauntless creature and one
alone, one solitary, inveterate worker, has produced the whole of
the prodigious mass. If work is the best way to enjoy life, this one
certainly has not been bored during the few weeks of her existence.

I gladly award her the most honourable of eulogies, that due to the
industrious; and I also compliment her on her talent for closing the
honey-pots. The pieces stacked into lids are round and have nothing
to suggest those of which the cells and the final barricade are made.
Excepting the first, those nearest the honey, they are perhaps cut a
little less neatly than the disks of the White-girdled Leaf-cutter; no
matter: they stop the jar perfectly, especially when there are some ten
of them one above the other. When cutting them, the Bee was as sure of
her scissors as a dressmaker guided by a pattern laid on the stuff; and
yet she was cutting without a model, without having in front of her the
mouth to be closed. To enlarge on this interesting subject would mean to
repeat oneself. All the Leaf-cutters have the same talent for making the
lids of their pots.

A less mysterious question than this geometrical problem is that of the
materials. Does each species of Megachile keep to a single plant, or
has it a definite botanical domain wherein to exercise its liberty of
choice? The little that I have already said is enough to make us suspect
that the insect is not restricted to one plant; and this is confirmed
by an examination of the separate cells, piece by piece, when we find a
variety which we were far from imagining at first. Here is the flora
of the Megachiles in my neighbourhood, a very incomplete flora and
doubtless capable of considerable amplification by future researches.

The Silky Leaf-cutter gathers the materials for her pots, her lids and
her barricades from the following plants: paliurus, hawthorn, vine,
wild briar, bramble, holm-oak, amelanchier, terebinthus, sage-leaved
rock-rose. The first three supply the greater part of the leaf-work; the
last three are represented only by rare fragments.

The Hare-footed Leaf-cutter (Megachile lagopoda, LIN.) which I see very
busy in my enclosure, though she only collects her materials there,
exploits the lilac and the rose-tree by preference. From time to time,
I see her also cutting bits out of the robinia, the quince-tree and the
cherry-tree. In the open country, I have found her building with the
leaves of the vine alone.

The Silvery Leaf-cutter (Megachile argentata, FAB.), another of my
guests, shares the taste of the aforesaid for the lilac and the rose,
but her domain includes in addition the pomegranate-tree, the bramble,
the vine, the common dogwood and the cornelian cherry.

The White-girdled Leaf-cutter likes the robinia, to which she adds, in
lavish proportions, the vine, the rose and the hawthorn and sometimes,
in moderation, the reed and the whitish-leaved rock-rose.

The Black-tipped Leaf-cutter (Megachile apicalis, SPIN.) has for her
abode the cells of the Mason-bee of the Pebbles and the ruined nests of
the Osmiae and Anthidia in the Snail-shells. I have not known her to use
any other materials than the wild briar and the hawthorn.

Incomplete though it be, this list tells us that the Megachiles do not
have exclusive botanical tastes. Each species manages extremely well
with several plants differing greatly in appearance. The first condition
to be fulfilled by the shrub exploited is that it be near the
nest. Frugal of her time, the Leaf-cutter declines to go on distant
expeditions. Whenever I come upon a recent Megachile-nest, I am not long
in finding in the neighbourhood, without much searching, the tree or
shrub from which the Bee has cut her pieces.

Another main condition is a fine and supple texture, especially for the
first disks used in the lid and for the pieces which form the lining of
the wallet. The rest, less carefully executed, allows of coarser
stuff; but even then the piece must be flexible and lend itself to the
cylindrical configuration of the tunnel. The leaves of the rock-roses,
thick and roughly fluted, fulfil this condition unsatisfactorily, for
which reason I see them occurring only at very rare intervals. The
insect has gathered pieces of them by mistake and, not finding them good
to use, has ceased to visit the unprofitable shrub. Stiffer still, the
leaf of the holm-oak in its full maturity is never employed: the Silky
Leaf-cutter uses it only in the young state and then in moderation; she
can get her velvety pieces better from the vine. In the lilac-bushes so
zealously exploited before my eyes by the Hare-footed Leaf-cutter occur
a medley of different shrubs which, from their size and the lustre of
their leaves, should apparently suit that sturdy pinker. They are the
shrubby hare's-ear, the honeysuckle, the prickly butcher's-broom, the
box. What magnificent disks ought to come from the hare's-ear and the
honeysuckle! One could get an excellent piece, without further labour,
by merely cutting the leaf-stalk of the box, as Megachile sericans does
with her paliurus. The lilac-lover disdains them absolutely. For
what reason? I fancy that she finds them too stiff. Would she think
differently if the lilac-bush were not there? Perhaps so.

In short, apart from the questions of texture and proximity to the
nest, the Megachile's choice, it seems to me, must depend upon whether a
particular shrub is plentiful or not. This would explain the lavish use
of the vine, an object of widespread cultivation, and of the hawthorn
and the wild briar, which form part of all our hedges. As these are to
be found everywhere, the fact that the different Leaf-cutters make use
of them is no reflection upon a host of equivalents varying according to
the locality.

If we had to believe what people tell us about the effects of heredity,
which is said to hand down from generation to generation, ever more
firmly established, the individual habits of those who come before, the
Megachiles of these parts, experienced in the local flora by the long
training of the centuries, but complete novices in the presence of
plants which their race encounters for the first time, ought to refuse
as unusual and suspicious any exotic leaves, especially when they have
at hand plenty of the leaves made familiar by hereditary custom. The
question was deserving of separate study.

Two subjects of my observations, the Hare-footed and the Silvery
Leaf-cutter, both of them inmates of my open-air laboratory, gave me a
definite answer. Knowing the points frequented by the two Megachiles,
I planted in their work-yard, overgrown with briar and lilac, two
outlandish plants which seemed to me to fulfil the required conditions
of suppleness of texture, namely, the ailantus, a native of Japan, and
the Virginian physostegia. Events justified the selection: both Bees
exploited the foreign flora with the same assiduity as the local
flora, passing from the lilac to the ailantus, from the briar to the
physostegia, leaving the one, going back to the other, without drawing
distinctions between the known and the unknown. Inveterate habit could
not have given greater certainty, greater ease to their scissors, though
this was their first experience of such a material.

The Silvery Leaf-cutter lent herself to an even more conclusive test. As
she readily makes her nest in the reeds of my apparatus, I was able,
up to a certain point, to create a landscape for her and select its
vegetation myself. I therefore moved the reed-hive to a part of the
enclosure stocked chiefly with rosemary, whose scanty foliage is not
adapted for the Bee's work, and near the apparatus I arranged an exotic
shrubbery in pots, including notably the smooth lopezia, from Mexico,
and the long-fruited capsicum, an Indian annual. Finding close at hand
the wherewithal to build her nest, the Leaf-cutter went no further
afield. The lopezia suited her especially, so much so that almost the
whole nest was composed of it. The rest had been gathered from the
capsicum.

Another recruit, whose co-operation I had in no way engineered, came
spontaneously to offer me her evidence. This was the Feeble Leaf-cutter
(Megachile imbecilla, GERST.). Nearly a quarter of a century ago, I saw
her, all through the month of July, cutting out her rounds and ellipses
at the expense of the petals of the Pelargonium zonale, the common
geranium. Her perseverance devastated--there is no other word for
it--my modest array of pots. Hardly was a blossom out, when the
ardent Megachiles came and scalloped it into crescents. The colour was
indifferent to her: red, white or pink, all the petals underwent
the disastrous operation. A few captures, ancient relics of my
collecting-boxes by this time, indemnified me for the pillage. I have
not seen this unpleasant Bee since. With what does she build when there
are no geranium-flowers handy? I do not know; but the fact remains that
the fragile tailoress used to attack the foreign flower, a fairly
recent acquisition from the Cape, as though all her race had never done
anything else.

These details leave us with one obvious conclusion, which is contrary to
our original ideas, based on the unvarying character of insect industry.
In constructing their jars, the Leaf-cutters, each following the taste
peculiar to her species, do not make use of this or that plant to
the exclusion of the others; they have no definite flora, no domain
faithfully transmitted by heredity. Their pieces of leaves vary
according to the surrounding vegetation; they vary in different layers
of the same cell. Everything suits them, exotic or native, rare or
common, provided that the bit cut out be easy to employ. It is not the
general aspect of the shrub, with its fragile or bushy branches, its
large or small, green or grey, dull or glossy leaves, that guides
the insect: such advanced botanical knowledge does not enter into the
question at all. In the thicket chosen as a pinking-establishment, the
Megachile sees but one thing: leaves useful for her work. The Shrike,
with his passion for plants with long, woolly sprigs, knows where
to find nicely-wadded substitutes when his favourite growth, the
cotton-rose, is lacking; the Megachile has much wider resources:
indifferent to the plant itself, she looks only into the foliage. If she
finds leaves of the proper size, of a dry texture capable of defying the
damp and of a suppleness favourable to cylindrical curving, that is
all she asks; and the rest does not matter. She has therefore an almost
unlimited field for her labour.

These sudden and wholly unprovoked changes give cause for reflection.
When my geranium-flowers were devastated, how had the obtrusive Bee,
untroubled by the profound dissimilarity between the petals, snow-white
here, bright scarlet there, how had she learnt her trade? Nothing tells
us that she herself was not for the first time exploiting the plant from
the Cape; and, if she really did have predecessors, the habit had not
had time to become inveterate, considering the modern importation of the
geranium. Where again did the Silvery Megachile, for whom I created an
exotic shrubbery, make the acquaintance of the lopezia, which comes from
Mexico? She certainly is making a first start. Never did her village or
mine possess a stalk of that chilly denizen of our hot-houses. She is
making a first start; and behold her straightway a graduate, versed in
the art of carving unfamiliar foliage.

People often talk of the long apprenticeships served by instinct, of its
gradual acquirements, of its talents, the laborious work of the ages.
The Megachiles affirm the exact opposite. They tell me that the animal,
though invariable in the essence of its art, is capable of innovation
in the details; but at the same time they assure me that any such
innovation is sudden and not gradual. Nothing prepares the innovations,
nothing improves them or hands them down; otherwise a selection would
long ago have been made amid the diversity of foliage; and the
shrub recognized as the most serviceable, especially when it is also
plentiful, would alone supply all the building-materials needed. If
heredity transmitted industrial discoveries, a Megachile who thought of
cutting her disks out of pomegranate-leaves and found them satisfactory
ought to have instilled a liking for similar materials into her
descendants; and we should this day find Leaf-cutters faithful to the
pomegranate-leaves, workers who remained exclusive in their choice of
the raw material. The facts refute these theories.

People also say:

'Grant us a variation, however small, in the insect's industry; and
that variation, accentuated more and more, will produce a new race and
finally a fixed species.'

This trifling variation is the fulcrum for which Archimedes clamoured in
order to lift the world with his system of levers. The Megachiles
offer us one and a very great one: the indefinite variation of their
materials. What will the theorists' levers lift with this fulcrum? Why,
nothing at all! Whether they cut the delicate petals of the geranium or
the tough leaves of the lilac-bushes, the Leaf-cutters are and will
be what they were. This is what we learn from the persistence of each
species in its structural details, despite the great variety of the
foliage employed.




CHAPTER 9. THE COTTON-BEES.

The evidence of the Leaf-cutters proves that a certain latitude is
left to the insect in its choice of materials for the nest; and this is
confirmed by the testimony of the Anthidia, the cotton-manufacturers.
My district possesses five: A. Florentinum, LATR., A. diadema, LATR., A.
manicatum, LATR., A. cingulatum, LATR., A. scapulare, LATR. None of them
creates the refuge in which the cotton goods are manufactured. Like the
Osmiae and the Leaf-cutters, they are homeless vagrants, adopting,
each to her own taste, such shelter as the work of others affords. The
Scapular Anthidium is loyal to the dry bramble, deprived of its pith and
turned into a hollow tube by the industry of various mining Bees, among
which figure, in the front rank, the Ceratinae, dwarf rivals of the
Xylocopa, or Carpenter-bee, that mighty driller of rotten wood.
The spacious galleries of the Masked Anthophora suit the Florentine
Anthidium, the foremost member of the genus so far as size is concerned.
The Diadem Anthidium considers that she has done very well if she
inherits the vestibule of the Hairy-footed Anthophora, or even the
ordinary burrow of the Earth-worm. Failing anything better, she may
establish herself in the dilapidated dome of the Mason-bee of the
Pebbles. The Manicate Anthidium shares her tastes. I have surprised the
Girdled Anthidium cohabiting with a Bembex-wasp. The two occupants of
the cave dug in the sand, the owner and the stranger, were living in
peace, both intent upon their business. Her usual habitation is some
hole or other in the crevices of a ruined wall. To these refuges, the
work of others, we can add the stumps of reeds, which are as popular
with the various cotton-gatherers as with the Osmiae; and, after we have
mentioned a few most unexpected retreats, such as the sheath provided
by a hollow brick or the labyrinth furnished by the lock of a gate, we
shall have almost exhausted the list of domiciles.

Like the Osmiae and the Leaf-cutters, the Anthidium shows an urgent need
of a ready-made home. She never houses herself at her own expense. Can
we discover the reason? Let us first consult a few hard workers who are
artificers of their own dwellings. The Anthophora digs corridors and
cells in the road-side banks hardened by the sun; she does not erect,
she excavates; she does not build, she clears. Toiling away with her
mandibles, atom by atom, she manages to contrive the passages and
chambers necessary for her eggs; and a huge business it is. She has, in
addition, to polish and glaze the rough sides of her tunnels. What would
happen if, after obtaining a home by dint of long-continued toil,
she had next to line it with wadding, to gather the fibrous down from
cottony plants and to felt it into bags suitable for the honey-paste?
The hard-working Bee would not be equal to producing all these
refinements. Her mining calls for too great an expenditure of time and
strength to leave her the leisure for luxurious furnishing. Chambers and
corridors, therefore, will remain bare.

The Carpenter-bee gives us the same answer. When with her joiner's
wimble she has patiently bored the beam to a depth of nine inches, would
she be able to cut out and place in position the thousand and one pieces
which the Silky Leaf-cutter employs for her nest? Time would fail her,
even as it would fail a Megachile who, lacking the Capricorn's chamber,
had herself to dig a home in the trunk of the oak. Therefore the
Carpenter-bee, after the tedious work of boring, gets the installation
done in the most summary fashion, simply running up a sawdust partition.

The two things, the laborious business of obtaining a lodging and the
artistic work of furnishing, seem unable to go together. With the
insect as with man, he who builds the house does not furnish it, he who
furnishes it does not build it. To each his share, because of lack of
time. Division of labour, the mother of the arts, makes the workman
excel in his department; one man for the whole work would mean
stagnation, the worker never getting beyond his first crude attempts.
Animal industry is a little like our own: it does not attain its
perfection save with the aid of obscure toilers, who, without knowing
it, prepare the final masterpiece. I see no other reason for this
need of a gratuitous lodging for the Megachile's leafy basket or the
Anthidia's cotton purses. In the case of other artists who handle
delicate things that require protection, I do not hesitate to assume
the existence of a ready-made home. Thus Reaumur tells us of the
Upholsterer-bee, Anthocopa papaveris, who fashions her cells with
poppy-petals. I do not know the flower-cutter, I have never seen her;
but her art tells me plainly enough that she must establish herself in
some gallery wrought by others, as, for instance, in an Earth-worm's
burrow.

We have but to see the nest of a Cotton-bee to convince ourselves that
its builder cannot at the same time be an indefatigable navvy. When and
newly-felted and not yet made sticky with honey, the wadded purse is
by far the most elegant known specimen of entomological nest-building,
especially where the cotton is of a brilliant white, as is frequently
the case in the manufacturers of the Girdled Anthidium. No bird's-nest,
however deserving of our admiration, can vie in fineness of flock, in
gracefulness of form, in delicacy of felting with this wonderful bag,
which our fingers, even with the aid of tools, could hardly imitate, for
all their dexterity. I abandon the attempt to understand how, with its
little bales of cotton brought up one by one, the insect, no otherwise
gifted than the kneaders of mud and the makers of leafy baskets, manages
to felt what it has collected into a homogeneous whole and then to work
the product into a thimble-shaped wallet. Its tools as a master-fuller
are its legs and its mandibles, which are just like those possessed by
the mortar-kneaders and Leaf-cutters; and yet, despite this similarity
of outfit, what a vast difference in the results obtained!

To see the Cotton-bees' talents in action seems an undertaking fraught
with innumerable difficulties: things happen at a depth inaccessible to
the eye; and to persuade the insect to work in the open does not lie
in our power. One resource remained and I did not fail to turn to
it, though hitherto I have been wholly unsuccessful. Three species,
Anthidium diadema, A. manicatum and A. florentinum--the first-named in
particular--show themselves quite ready to take up their abode in my
reed-apparatus. All that I had to do was to replace the reeds by glass
tubes, which would allow me to watch the work without disturbing the
insect. This stratagem had answered perfectly with the Three-horned
Osmia and Latreille's Osmia, whose little housekeeping-secrets I had
learnt thanks to the transparent dwelling-house. Why should it not
answer for its Cotton-bees and, in the same way, with the Leaf-cutters?
I almost counted on success. Events betrayed my confidence. For
four years I supplied my hives with glass tubes and not once did the
Cotton-weavers or the Leaf-cutters condescend to take up their quarters
in the crystal palaces. They always preferred the hovel provided by the
reed. Shall I persuade them one day? I do not abandon all hope.

Meanwhile, let me describe the little that I saw. More or less stocked
with cells, the reed is at last closed, right at the orifice, with
a thick plug of cotton, usually coarser than the wadding of the
honey-satchels. It is the equivalent of the Three-horned Osmia's
barricade of mud, of the leaf-putty of Latreille's Osmia, of the
Megachiles' barrier of leaves cut into disks. All these free tenants are
careful to shut tight the door of the dwelling, of which they have often
utilized only a portion. To watch the building of this barricade, which
is almost external work, demands but a little patience in waiting for
the favourable moment.

The Anthidium arrives at last, carrying the bale of cotton for the
plugging. With her fore-legs she tears it apart and spreads it out; with
her mandibles, which go in closed and come out open, she loosens the
hard lumps of flock; with her forehead she presses each new layer upon
the one below. And that is all. The insect flies off, returns the richer
by another bale and repeats the performance until the cotton barrier
reaches the level of the opening. We have here, remember, a rough task,
in no way to be compared with the delicate manufacturer of the bags;
nevertheless, it may perhaps tell us something of the general procedure
of the finer work. The legs do the carding, the mandibles the dividing,
the forehead the pressing; and the play of these implements produces the
wonderful cushioned wallet. That is the mechanism in the lump; but what
of the artistry?

Let us leave the unknown for facts within the scope of observation. I
will question the Diadem Anthidium in particular, a frequent inmate
of my reeds. I open a reed-stump about two decimetres long by twelve
millimetres in diameter. (About seven and three-quarter inches by
half an inch.--Translator's Note.) The end is occupied by a column of
cotton-wool comprising ten cells, without any demarcation between
them on the outside, so that their whole forms a continuous cylinder.
Moreover, thanks to a close felting, the different compartments are
soldered together, so much so that, when pulled by the end, the cotton
edifice does not break into sections, but comes out all in one piece.
One would take it for a single cylinder, whereas in reality the work
is composed of a series of chambers, each of which has been constructed
separately, independently of the one before, except perhaps at the base.

For this reason, short of ripping up the soft dwelling, still full of
honey, it is impossible to ascertain the number of storeys; we must
wait until the cocoons are woven. Then our fingers can tell the cells by
counting the knots that resist pressure under the cover of wadding. This
general structure is easily explained. A cotton bag is made, with the
sheath of the reed as a mould. If this guiding sheath were lacking, the
thimble shape would be obtained all the same, with no less elegance,
as is proved by the Girdled Anthidium, who makes her nest in some
hiding-place or other in the walls or the ground. When the purse is
finished, the provisions come and the egg, followed by the closing of
the cell. We do not here find the geometrical lid of the Leaf-cutters,
the pile of disks tight-set in the mouth of the jar. The bag is closed
with a cotton sheet whose edges are soldered by a felting-process to the
edges of the opening. The soldering is so well done that the honey-pouch
and its cover form an indivisible whole. Immediately above it, the
second cell is constructed, having its own base. At the beginning of
this work, the insect takes care to join the two storeys by felting the
ceiling of the first to the floor of the second. Thus continued to the
end, the work, with its inner solderings, becomes an unbroken cylinder,
in which the beauties of the separate wallets disappear from view. In
very much the same fashion, but with less adhesion among the different
cells, do the Leaf-cutters act when stacking their jars in a column
without any external division into storeys.

Let us return to the reed-stump which gives us these details. Beyond the
cotton-wool cylinder wherein ten cocoons are lodged in a row comes
an empty space of half a decimetre or more. (About two
inches.--Translator's Note.) The Osmiae and the Leaf-cutters are also
accustomed to leave these long, deserted vestibules. The nest ends, at
the orifice of the reed, with a strong plug of flock coarser and less
white than that of the cells. This use of closing-materials which are
less delicate in texture but of greater resisting-power, while not an
invariable characteristic, occurs frequently enough to make us suspect
that the insect knows how to distinguish what is best suited now to the
snug sleeping-berth of the larvae, anon to the defensive barricade of
the home. Sometimes the choice is an exceedingly judicious one, as is
shown by the nest of the Diadem Anthidium. Time after time, whereas the
cells were composed of the finest grade of white cotton, gathered from
Centaurea solsticialis, or St. Barnaby's thistle, the barrier at the
entrance, differing from the rest of the work in its yellow colouring,
was a heap of close-set bristles supplied by the scallop-leaved mullein.
The two functions of the wadding are here plainly marked. The delicate
skin of the larvae needs a well-padded cradle; and the mother collects
the softest materials that the cottony plants provide. Rivalling the
bird, which furnishes the inside of the nest with wool and strengthens
the outside with sticks, she reserves for the grubs' mattress the finest
down, so hard to find and collected with such patience. But, when it
becomes a matter of shutting the door against the foe, then the entrance
bristles with forbidding caltrops, with stiff, prickly hairs.

This ingenious system of defence is not the only one known to the
Anthidia. More distrustful still, the Manicate Anthidium leaves no space
in the front part of the reed. Immediately after the column of cells,
she heaps up, in the uninhabited vestibule, a conglomeration of rubbish,
whatever chance may offer in the neighbourhood of the nest: little
pieces of gravel, bits of earth, grains of sawdust, particles of mortar,
cypress-catkins, broken leaves, dry Snail-droppings and any other
material that comes her way. The pile, a real barricade this time,
blocks the reed completely to the end, except about two centimetres
(About three-quarters of an inch.--Translator's Note.) left for the
final cotton plug. Certainly no foe will break in through the double
rampart; but he will make an insidious attack from the rear.
The Leucopsis will come and, with her long probe, thanks to some
imperceptible fissure in the tube, will insert her dread eggs and
destroy every single inhabitant of the fortress. Thus are the Manicate
Anthidium's anxious precautions outwitted.

If we had not already seen the same thing with the Leaf-cutters, this
would be the place to enlarge upon the useless tasks undertaken by the
insect when, with its ovaries apparently depleted, it goes on spending
its strength with no maternal object in view and for the sole pleasure
of work. I have come across several reeds stopped up with flock though
containing nothing at all, or else furnished with one, two or three
cells devoid of provisions or eggs. The ever-imperious instinct
for gathering cotton and felting it into purses and heaping it into
barricades persists, fruitlessly, until life fails. The Lizard's tail
wriggles, curls and uncurls after it is detached from the animal's body.
In these reflex movements, I seem to see not an explanation, certainly,
but a rough image of the industrious persistency of the insect, still
toiling away at its business, even when there is nothing useful left to
do. This worker knows no rest but death.

I have said enough about the dwelling of the Diadem Anthidium; let us
look at the inhabitant and her provisions. The honey is pale-yellow,
homogeneous and of a semifluid consistency, which prevents it from
trickling through the porous cotton bag. The egg floats on the surface
of the heap, with the end containing the head dipped into the paste. To
follow the larva through its progressive stages is not without interest,
especially on account of the cocoon, which is one of the most singular
that I know. With this object in view, I prepare a few cells that lend
themselves to observation. I take a pair of scissors, slice a piece off
the side of the cotton-wool purse, so as to lay bare both the victuals
and the consumer, and place the ripped cell in a short glass tube.
During the first few days, nothing striking happens. The little grub,
with its head still plunged in the honey, slakes its thirst with long
draughts and waxes fat. A moment comes...But let us go back a little
farther, before broaching this question of sanitation.

Every grub, of whatever kind, fed on provisions collected by the mother
and placed in a narrow cell is subject to conditions of health unknown
to the roving grub that goes where it likes and feeds itself on what it
can pick up. The first, the recluse, is no more able than the second,
the gadabout, to solve the problem of a food which can be entirely
assimilated, without leaving an unclean residue. The second gives no
thought to these sordid matters: any place suits it for getting rid
of that difficulty. But what will the other do with its waste matter,
cooped up as it is in a tiny cell stuffed full of provisions? A most
unpleasant mixture seems inevitable. Picture the honey-eating grub
floating on liquid provisions and fouling them at intervals with its
excretions! The least movement of the hinder-part would cause the
whole to amalgamate; and what a broth that would make for the delicate
nursling! No, it cannot be; those dainty epicures must have some method
of escaping these horrors.

They all have, in fact, and most original methods at that. Some take
the bull by the horns, so to speak, and, in order not to soil things,
refrain from uncleanliness until the end of the meal: they keep the
dropping-trap closed as long as the victuals are unfinished. This is
a radical scheme, but not in every one's power, it appears. It is
the course adopted, for instance, by the Sphex-wasps and the
Anthophora-bees, who, when the whole of the food is consumed, expel at
one shot the residues amassed in the intestines since the commencement
of the repast.

Others, the Osmiae in particular, accept a compromise and begin to
relieve the digestive tract when a suitable space has been made in
the cell through the gradual disappearance of the victuals. Others
again--more hurried these--find means of obeying the common law pretty
early by engaging in stercoral manufactures. By a stroke of genius, they
make the unpleasant obstruction into building-bricks. We already know
the art of the Lily-beetle (Crioceris merdigera. Fabre's essay on this
insect has not yet been translated into English; but readers interested
in the matter will find a full description in "An Introduction to
Entomology," by William Kirby, Rector of Barham, and William Spence:
letter 21.--Translator's Note.), who, with her soft excrement, makes
herself a coat wherein to keep cool in spite of the sun. It is a very
crude and revolting art, disgusting to the eye. The Diadem Anthidium
belongs to another school. With her droppings she fashions masterpieces
of marquetry and mosaic, which wholly conceal their base origin from the
onlooker. Let us watch her labours through the windows of my tubes.

When the portion of food is nearly half consumed, there begins and goes
on to the end a frequent defecation of yellowish droppings, each hardly
the size of a pin's head. As these are ejected, the grub pushes them
back to the circumference of the cell with a movement of its hinder-part
and keeps them there by means of a few threads of silk. The work of
the spinnerets, therefore, which is deferred in the others until the
provisions are finished, starts earlier here and alternates with the
feeding. In this way, the excretions are kept at a distance, away from
the honey and without any danger of getting mixed with it. They end by
becoming so numerous as to form an almost continuous screen around the
larva. This excremental awning, made half of silk and half of droppings,
is the rough draft of the cocoon, or rather a sort of scaffolding on
which the stones are deposited until they are definitely placed in
position. Pending the piecing together of the mosaic, the scaffolding
keeps the victuals free from all contamination.

To get rid of what cannot be flung outside, by hanging it on the
ceiling, is not bad to begin with; but to use it for making a work of
art is better still. The honey has disappeared. Now commences the final
weaving of the cocoon. The grub surrounds itself with a wall of silk,
first pure white, then tinted reddish-brown by means of an adhesive
varnish. Through its loose-meshed stuff, it seizes one by one the
droppings hanging from the scaffold and inlays them firmly in the
tissue. The same mode of work is employed by the Bembex-, Stizus-and
Tachytes-wasps and other inlayers, who strengthen the inadequate woof
of their cocoons with grains of sand; only, in their cotton-wool purses,
the Anthidium's grubs substitute for the mineral particles the only
solid materials at their disposal. For them, excrement takes the place
of pebbles.

And the work goes none the worse for it. On the contrary: when the
cocoon is finished, any one who had not witnessed the process of
manufacture would be greatly puzzled to state the nature of the
workmanship. The colouring and the elegant regularity of the outer
wrapper of the cocoon suggest some kind of basket-work made with tiny
bits of bamboo, or a marquetry of exotic granules. I too let myself be
caught by it in my early days and wondered in vain what the hermit of
the cotton wallet had used to inlay her nymphal dwelling so prettily
withal. To-day, when the secret is known to me, I admire the ingenuity
of the insect capable of obtaining the useful and the beautiful out of
the basest materials.

The cocoon has another surprise in store for us. The end containing the
head finishes with a short conical nipple, an apex, pierced by a narrow
shaft that establishes a communication between the inside and the
out. This architectural feature is common to all the Anthidia, to the
resin-workers who will occupy our attention presently, as well as to the
cotton-workers. It is found nowhere outside the Anthidium group.

What is the use of this point which the larva leaves bare instead of
inlaying it like the rest of the shell? What is the use of that hole,
left quite open or, at most, closed at the bottom with a feeble grating
of silk? The insect appears to attach great importance to it, from what
I see. In point of fact, I watch the careful work of the apex. The grub,
whose movements the hole enables me to follow, patiently perfects the
lower end of the conical channel, polishes it and gives it an exactly
circular shape; from time to time, it inserts into the passage its
two closed mandibles, whose points project a little way outside; then,
opening them to a definite radius, like a pair of compasses, it widens
the aperture and makes it regular.

I imagine, without venturing, however, to make a categorical statement,
that the perforated apex is a chimney to admit the air required for
breathing. Every pupa breathes in its shell, however compact this may
be, even as the unhatched bird breathes inside the egg. The thousands
of pores with which the shell is pierced allow the inside moisture to
evaporate and the outer air to penetrate as and when needed. The stony
caskets of the Bembex- and Stizus-wasps are endowed, notwithstanding
their hardness, with similar means of exchange between the vitiated and
the pure atmosphere. Can the shells of the Anthidia be air-proof, owing
to some modification that escapes me? In any case, this impermeability
cannot be attributed to the excremental mosaic, which the cocoons of the
resin-working Anthidia do not possess, though endowed with an apex of
the very best.

Shall we find an answer to the question in the varnish with which the
silken fabric is impregnated? I hesitate to say yes and I hesitate to
say no, for a host of cocoons are coated with a similar lacquer though
deprived of communication with the outside air. All said, without being
able at present to account for its necessity, I admit that the apex of
the Anthidia is a breathing-aperture. I bequeath to the future the task
of telling us for what reasons the collectors of both cotton and resin
leave a large pore in their shells, whereas all the other weavers close
theirs completely.

After these biological curiosities, it remains for me to discuss the
principal subject of this chapter: the botanical origin of the materials
of the nest. By watching the insect when busy at its harvesting, or else
by examining its manufactured flock under the microscope, I was able to
learn, not without a great expenditure of time and patience, that the
different Anthidia of my neighbourhood have recourse without distinction
to any cottony plant. Most of the wadding is supplied by the Compositae,
particularly the following: Centaurea solsticialis, or St. Barnaby's
thistle; C. paniculata, or panicled centaury; Echinops ritro, or
small globe-thistle; Onopordon illyricum, or Illyrian cotton-thistle;
Helichrysum staechas, or wild everlasting; Filago germanica, or common
cotton-rose. Next come the Labiatae: Marrubium vulgare, or common white
horehound; Ballota fetida, or stinking horehound; Calamintha nepeta,
or lesser calamint; Salvia aethiopis, or woolly sage. Lastly, the
Solanaceae: Verbascum thapsus, or shepherd's club; V. sinuatum, or
scollop-leaved mullein.

The Cotton-bees' flora, we see, incomplete as it is in my notes,
embraces plants of very different aspect. There is no resemblance in
appearance between the proud candelabrum of the cotton-thistle, with its
red tufts, and the humble stalk of the globe-thistle, with its sky-blue
capitula; between the plentiful leaves of the mullein and the scanty
foliage of the St. Barnaby's thistle; between the rich silvery fleece
of the woolly sage and the short hairs of the everlasting. With the
Anthidium, these clumsy botanical characteristics do not count; one
thing alone guides her: the presence of cotton. Provided that the plant
be more or less well-covered with soft wadding, the rest is immaterial
to her.

Another condition, however, has to be fulfilled, apart from the fineness
of the cotton-wool. The plant, to be worth shearing, must be dead and
dry. I have never seen the harvesting done on fresh plants. In this
way, the Bee avoids mildew, which would make its appearance in a mass of
hairs still filled with sap.

Faithful to the plant recognized as yielding good results, the Anthidium
arrives and resumes her gleaning on the edges of the parts denuded by
earlier harvests. Her mandibles scrape away and pass the tiny fluffs,
one by one, to the hind-legs, which hold the pellet pressed against the
chest, mix with it the rapidly-increasing store of down and make the
whole into a little ball. When this is the size of a pea, it goes back
into the mandibles; and the insect flies off, with its bale of cotton
in its mouth. If we have the patience to wait, we shall see it return to
the same point, at intervals of a few minutes, so long as the bag is not
made. The foraging for provisions will suspend the collecting of cotton;
then, next day or the day after, the scraping will be resumed on the
same stalk, on the same leaf, if the fleece be not exhausted. The owner
of a rich crop appears to keep to it until the closing-plug calls for
coarser materials; and even then this plug is often manufactured with
the same fine flock as the cells.

After ascertaining the diversity of cotton-fields among our native
plants, I naturally had to enquire whether the Cotton-bee would also
put up with exotic plants, unknown to her race; whether the insect would
show any hesitation in the presence of woolly plants offered for the
first time to the rakes of her mandibles. The common clary and the
Babylonian centaury, with which I have stocked the harmas, shall be the
harvest-fields; the reaper shall be the Diadem Anthidium, the inmate of
my reeds.

The common clary, or toute-bonne, forms part, I know, of our French
flora to-day; but it is an acclimatized foreigner. They say that a
gallant crusader, returning from Palestine with his share of glory and
bruises, brought back the toute-bonne from the Levant to help him cure
his rheumatism and dress his wounds. From the lordly manor, the plant
propagated itself in all directions, while remaining faithful to the
walls under whose shelter the noble dames of yore used to grow it for
their unguents. To this day, feudal ruins are its favourite resorts.
Crusaders and manors disappeared; the plant remained. In this case, the
origin of the clary, whether historical or legendary, is of secondary
importance. Even if it were of spontaneous growth in certain parts
of France, the toute-bonne is undoubtedly a stranger in the Vaucluse
district. Only once in the course of my long botanizing-expeditions
across the department have I come upon this plant. It was at Caromb, in
some ruins, nearly thirty years ago. I took a cutting of it; and since
then the crusaders' sage has accompanied me on all my peregrinations.
My present hermitage possesses several tufts of it: but, outside the
enclosure, except at the foot of the walls, it would be impossible to
find one. We have, therefore, a plant that is new to the country for
many miles around, a cotton-field which the Serignan Cotton-bees had
never utilized before I came and sowed it.

Nor had they ever made use of the Babylonian centaury, which I was the
first to introduce in order to cover my ungrateful stony soil with
some little vegetation. They had never seen anything like the colossal
centaury imported from the region of the Euphrates. Nothing in the local
flora, not even the cotton-thistle, had prepared them for this stalk
as thick as a child's wrist, crowned at a height of nine feet with a
multitude of yellow balls, nor for those great leaves spreading over the
ground in an enormous rosette. What will they do in the presence of such
a find? They will take possession of it with no more hesitation than if
it were the humble St. Barnaby's thistle, the usual purveyor.

In fact, I place a few stalks of clary and Babylonian centaury,
duly dried, near the reed-hives. The Diadem Anthidium is not long in
discovering the rich harvest. Straight away the wool is recognized as
being of excellent quality, so much so that, during the three or four
weeks of nest-building, I can daily witness the gleaning, now on the
clary, now on the centaury. Nevertheless the Babylonian plant appears to
be preferred, no doubt because of its whiter, finer and more plentiful
down. I keep a watchful eye on the scraping of the mandibles and the
work of the legs as they prepare the pellet; and I see nothing
that differs from the operations of the insect when gleaning on
the globe-thistle and the St. Barnaby's thistle. The plant from the
Euphrates and the plant from Palestine are treated like those of the
district.

Thus we find what the Leaf-cutters taught us proved, in another way,
by the cotton-gatherers. In the local flora, the insect has no precise
domain; it reaps its harvest readily now from one species, now from
another, provided that it find the materials for its manufactures. The
exotic plant is accepted quite as easily as that of indigenous growth.
Lastly, the change from one plant to another, from the common to the
rare, from the habitual to the exceptional, from the known to the
unknown, is made suddenly, without gradual initiations. There is no
novitiate, no training by habit in the choice of the materials for
the nest. The insect's industry, variable in its details by sudden,
individual and non-transmissible innovations, gives the lie to the two
great factors of evolution: time and heredity.




CHAPTER 10. THE RESIN-BEES.

At the time when Fabricius (Johann Christian Fabricius (1745-1808),
a noted Danish entomologist, author of "Systema entomologiae"
(1775).--Translator's Note.) gave the genus Anthidium its name, a name
still used in our classifications, entomologists troubled very little
about the live animal; they worked on corpses, a dissecting-room method
which does not yet seem to be drawing to an end. They would examine
with a conscientious eye the antenna, the mandible, the wing, the leg,
without asking themselves what use the insect had made of those organs
in the exercise of its calling. The animal was classified very nearly
after the manner adopted in crystallography. Structure was everything;
life, with its highest prerogatives, intellect, instinct, did not count,
was not worthy of admission into the zoological scheme.

It is true that an almost exclusively necrological study is obligatory
at first. To fill one's boxes with insects stuck on pins is an operation
within the reach of all; to watch those same insects in their mode of
life, their work, their habits and customs is quite a different
thing. The nomenclator who lacks the time--and sometimes also the
inclination--takes his magnifying-glass, analyzes the dead body
and names the worker without knowing its work. Hence the number of
appellations the least of whose faults is that they are unpleasant to
the ear, certain of them, indeed, being gross misnomers. Have we not,
for instance, seen the name of Lithurgus, or stone-worker, given to a
Bee who works in wood and nothing but wood? Such absurdities will be
inevitable until the animal's profession is sufficiently familiar to
lend its aid in the compiling of diagnoses. I trust that the future will
see this magnificent advance in entomological science: men will reflect
that the impaled specimens in our collections once lived and followed
a trade; and anatomy will be kept in its proper place and made to leave
due room for biology.

Fabricius did not commit himself with his expression Anthidium, which
alludes to the love of flowers, but neither did he mention anything
characteristic: as all Bees have the same passion in a very high degree,
I see no reason to treat the Anthidia as more zealous looters than the
others. If he had known their cotton nests, perhaps the Scandinavian
naturalist would have given them a more logical denomination. As for me,
in a language wherein technical parade is out of place, I will call them
the Cotton-bees.

The term requires some limiting. To judge by my finds, in fact, the old
genus Anthidium, that of the classifying entomologists, comprises in my
district two very different corporations. One is known to us and works
exclusively in wadding; the other, which we are about to study, works in
resin, without ever having recourse to cotton. Faithful to my extremely
simple principle of defining the worker, as far as possible, by his
work, I will call the members of this guild the Resin-bees. Thus
confining myself to the data supplied by my observations, I divide the
Anthidium group into equal sections, of equal importance, for which I
demand special generic titles; for it is highly illogical to call the
carders of wool and the kneaders of resin by the same name. I surrender
to those whom it concerns the honour of effecting this reform in the
orthodox fashion.

Good luck, the friend of the persevering, made me acquainted in
different parts of Vaucluse with four Resin-bees whose singular trade
no one had yet suspected. To-day, I find them all four again in my own
neighbourhood. They are the following: Anthidium septemdentatum, LATR.,
A. bellicosum, LEP., A. quadrilobum, LEP., and A. Latreillii, LEP.
The first two make their nests in deserted Snail-shells; the other two
shelter their groups of cells sometimes in the ground, sometimes under a
large stone. We will first discuss the inhabitants of the Snail-shell.
I made a brief reference to them in an earlier chapter, when speaking of
the distribution of the sexes. This mere allusion, suggested by a study
of a different kind, must now be amplified. I return to it with fuller
particulars.

The stone-heaps in the Roman quarries near Serignan, which I have so
often visited in search of the nests of the Osmia who takes up her abode
in Snail-shells, supply me also with the two Resin-bees installed
in similar quarters. When the Field-mouse has left behind him a rich
collection of empty shells scattered all round his hay mattress under
the slab, there is always a hope of finding some Snail-shells plugged
with mud and, here and there, mixed with them, a few Snail-shells closed
with resin. The two Bees work next door to each other, one using clay,
the other gum. The excellence of the locality is responsible for this
frequent cohabitation, shelter being provided by the broken stone from
the quarry and lodgings by the shells which the Mouse has left behind.

At places where dead Snail-shells are few and far between, as in the
crevices of rustic walls, each Bee occupies by herself the shells which
she has found. But here, in the quarries, our crop will certainly be
a double or even a treble one, for both Resin-bees frequent the same
heaps. Let us, therefore, lift the stones and dig into the mound until
the excessive dampness of the subsoil tells us that it is useless to
look lower down. Sometimes at the moment of removing the first layer,
sometimes at a depth of eighteen inches, we shall find the Osmia's
Snail-shell and, much more rarely, the Resin-bee's. Above all, patience!
The job is none of the most fruitful; nor is it exactly an agreeable
one. By dint of turning over uncommonly jagged stones, our fingertips
get hurt, lose their skin and become as smooth as though we had held
them on a grindstone. After a whole afternoon of this work, our back
will be aching, our fingers will be itching and smarting and we shall
possess a dozen Osmia-nests and perhaps two or three Resin-bees' nests.
Let us be content with that.

The Osmia's shells can be recognized at once, as being closed at
the orifice with a clay cover. The Anthidium's call for a special
examination, without which we should run a great risk of filling our
pockets with cumbersome rubbish. We find a dead Snail-shell among the
stones. Is it inhabited by the Resin-bee or not? The outside tells us
nothing. The Anthidium's work comes at the bottom of the spiral, a long
way from the mouth; and, though this is wide open, the eye cannot travel
far enough along the winding stair. I hold up the doubtful shell to the
light. If it is completely transparent, I know that it is empty and I
put it back to serve for future nests. If the second whorl is opaque,
the spiral contains something. What does it contain? Earth washed in by
the rain? Remnants of the putrefied Snail? That remains to be seen.
With a little pocket-trowel, the inquisitorial implement which always
accompanies me, I make a wide window in the middle of the final whorl.
If I see a gleaming resin floor, with incrustations of gravel, the
thing is settled: I possess an Anthidium's nest. But, oh the number of
failures that go to one success! The number of windows vainly opened in
shells whose bottom is stuffed with clay or with noisome corpses! Thus
picking shells among the overturned stone-heaps, inspecting them in
the sun, breaking into them with the trowel and nearly always rejecting
them, I manage, after repeated attempts, to obtain my materials for this
chapter.

The first to hatch is the Seven-pronged Resin-bee (Anthidium
septemdentatum). We see her, in the month of April, lumbering along to
the rubbish-heaps in the quarries and the low boundary-walls, in search
of her Snail-shell. She is a contemporary of the Three-horned Osmia, who
begins operations in the last week of April, and often occupies the same
stone-heap, settling in the next shell. She is well-advised to start
work early and to be on neighbourly terms with the Osmia when the latter
is building; in fact, we shall soon see the terrible dangers to which
that same proximity exposes her dilatory rival in resin-work, Anthidium
bellicosum.

The shell adopted in the great majority of cases is that of the
Common Snail, Helix aspersa. It is sometimes of full size, sometimes
half-developed. Helix nemoralis and H. caespitum, which are much
smaller, also supply suitable lodgings; and this would as surely apply
to any shell of sufficient capacity, if the places which I explore
possessed others, as witness a nest which my son Emile has sent me from
somewhere near Marseilles. This time, the Resin-bee is settled in Helix
algira, the most remarkable of our land-shells because of the width and
regularity of its spiral, which is copied from that of the Ammonites.
This magnificent nest, a perfect specimen of both the Snail's work and
the Bee's, deserves description before any other.

For a distance of three centimetres (1.17 inches.--Translator's
Note.) from the mouth, the last spiral whorl contains nothing. At this
inconsiderable depth, a partition is clearly seen. The moderate diameter
of the passage accounts for the Anthidium's choice of this site to which
our eye can penetrate. In the common Snail-shell, whose cavity widens
rapidly, the insect establishes itself much farther back, so that, in
order to see the terminal partition, we must, as I have said, make a
lateral inlet. The position of this boundary-ceiling, which may come
farther forward or farther back, depends on the variable diameter of the
passage. The cells of the cocoons require a certain length and a certain
breadth, which the mother finds by going higher up or lower down in
the spiral, according to the shape of the shell. When the diameter is
suitable, the last whorl is occupied up to the orifice, where the final
lid appears, absolutely exposed to view. This is the case with the adult
Helix nemoralis and H. caespitum, and also with the young Common Snail.
We will not linger at present over this peculiarity, the importance of
which will become manifest shortly.

Whether in the front or at the back of the spiral slope, the insect's
work ends in a facade of coarse mosaic, formed of small, angular bits
of gravel, firmly cemented with a gum the nature of which has to
be ascertained. It is an amber-coloured material, semi-transparent,
brittle, soluble in spirits of wine and burning with a sooty flame and a
strong smell of resin. From these characteristics it is evident that the
Bee prepares her gum with the resinous drops exuded by the Coniferae.

I think that I am even able to name the particular plant, though I have
never caught the insect in the act of gathering its materials. Hard
by the stone-heaps which I turn over for my collections there is a
plentiful supply of brown-berried junipers. Pines are totally absent;
and the cypress only appears occasionally near the houses. Moreover,
among the vegetable remains which we shall see assisting in the
protection of the nest, we often find the juniper's catkins and needles.
As the resin-insect is economical of its time and does not fly far from
the quarters familiar to it, the gum must have been collected on the
shrub at whose foot the materials for the barricade have been gathered.
Nor is this merely a local circumstance, for the Marseilles nest abounds
in similar remnants. I therefore regard the juniper as the regular
resin-purveyor, without, however, excluding the pine, the cypress and
other Coniferae when the favourite shrub is absent.

The bits of gravel in the lid are angular and chalky in the Marseilles
nest; they are round and flinty in most of the Serignan nests. In
making her mosaic, the worker pays no heed to the form or colour of its
component parts; she collects indiscriminately anything that is hard
enough and not too large. Sometimes she lights upon treasures that give
her work a more original character. The Marseilles nest shows me, neatly
encrusted amid the bits of gravel, a tiny whole landshell, Pupa cineres.
A nest in my own neighbourhood provides me with a pretty Snail-shell,
Helix striata, forming a rose-pattern in the middle of the mosaic. These
little artistic details remind me of a certain nest of Eumenes Amadei
(A Mason-wasp, forming the subject of an essay which has not yet been
published in English.--Translator's Note.) which abounds in small
shells. Ornamental shell-work appears to number its lovers among the
insects.

After the lid of resin and gravel, an entire whorl of the spiral is
occupied by a barricade of incongruous remnants, similar to that which,
in the reeds, protects the row of cocoons of the Manicate Cotton-bee.
It is curious to see exactly the same defensive methods employed by two
builders of such different talents, one of whom handles flock, the
other gum. The nest from Marseilles has for its barricade bits of chalky
gravel, particles of earth, fragments of sticks, a few scraps of
moss and especially juniper-catkins and needles. The Serignan nests,
installed in Helix aspersa, have almost the same protective materials. I
see bits of gravel, the size of a lentil, and the catkins and needles of
the brown-berried juniper predominating. Next come the dry excretions of
the Snail and a few rare little land-shells. A similar jumble of more or
less everything found near the nest forms, as we know, the barricade
of the Manicate Cotton-bee, who is also an adept at using the Snail's
stercoral droppings after these have been dried in the sun. Let us
observe finally that these dissimilar materials are heaped together
without any cementing, just as the insect has picked them up. Resin
plays no part in the mass; and we have only to pierce the lid and turn
the shell upside down for the barricade to come dribbling to the ground.
To glue the whole thing together does not enter into the Resin-bee's
scheme. Perhaps such an expenditure of gum is beyond her means; perhaps
the barricade, if hardened into a solid block, would afterwards form an
invincible obstacle to the escape of the youngsters; perhaps again the
mass of gravel is an accessory rampart, run up roughly as a work of
secondary importance.

Amid these doubtful matters, I see at least that the insect does not
look upon its barricade as indispensable. It employs it regularly in
the large shells, whose last whorl, too spacious to be used, forms an
unoccupied vestibule; it neglects it in the moderate shells, such as
Helix nemoralis, in which the resin lid is level with the orifice. My
excavations in the stone-heaps supply me with an almost equal number of
nests with and without defensive embankments. Among the Cotton-bees, the
Manicate Anthidium is not faithful either to her fort of little sticks
and stones; I know some of her nests in which cotton serves every
purpose. With both of them, the gravel rampart seems useful only in
certain circumstances, which I am unable to specify.

On the other side of the outworks of the fortification, the lid and
barricade, are the cells set more or less far down in the spiral,
according to the diameter of the shell. They are bounded back and
front by partitions of pure resin, without any encrustations of mineral
particles. Their number is exceedingly restricted and is usually limited
to two. The front room, which is larger because the width of the passage
goes on increasing, is the abode of a male, superior in size to the
other sex; the less spacious back room contains a female. I have already
drawn attention in an earlier chapter to the wonderful problem submitted
for our consideration by this breaking up of the laying into couples
and this alternation of the males and females. Without calling for other
work than the transverse partitions, the broadening stairway of the
Snail-shell thus furnishes both sexes with house-room suited to their
size.

The second Resin-bee that inhabits shells, Anthidium bellicosum, hatches
in July and works during the fierce heat of August. Her architecture
differs in no wise from that of her kinswoman of the springtime, so much
so that, when we find a tenanted Snail-shell in a hole in the wall or
under the stones, it is impossible to decide to which of the two species
the nest belongs. The only way to obtain exact information is to break
the shell and split the cocoons in February, at which time the nests
of the summer Resin-bee are occupied by larvae and those of the spring
Resin-bee by the perfect insect. If we shrink from this brutal
method, we are still in doubt until the cocoons open, so great is the
resemblance between the two pieces of work.

In both cases, we find the same lodging, Snail-shells of every size and
every kind, just as they happen to come; the same resin lid, the inside
gritty with tiny bits of stone, the outside almost smooth and
sometimes ornamented with little shells; the same barricade--not always
present--of various kinds of rubbish; the same division into two rooms
of unequal size occupied by the two sexes. Everything is identical, down
to the purveyor of the gum, the brown-berried juniper. To say more about
the nest of the summer Resin-bee would be to repeat oneself.

There is only one thing that requires further investigation. I do not
see the reason that prompts the two insects to leave the greater part of
their shell empty in front, instead of occupying it entirely up to the
orifice as the Osmia habitually does. As the mother's laying is broken
up into intermittent shifts of a couple of eggs apiece, is it necessary
that there should be a new home for each shift? Is the half-fluid resin
unsuitable for the wide-spanned roofs which would have to be constructed
when the diameter of the helical passage exceeded certain limits? Is
the gathering of the cement too wearisome a task to leave the Bee any
strength for making the numerous partitions which she would need if she
utilized the spacious final whorl? I find no answer to these questions.
I note the fact without interpreting it: when the shell is a large one,
the front part, almost the whole of the last whorl, remains an empty
vestibule.

To the spring Resin-bee, Anthidium septemdentatum, this less than half
occupied lodging presents no drawbacks. A contemporary of the Osmia,
often her neighbour under the same stone, the gum-worker builds her nest
at the same period as the mud-worker; but there is no fear of mutual
encroachments, for the two Bees, working next door to each other,
watch their respective properties with a jealous eye. If attempts at
usurpation were to be made, the owner of the Snail-shell would know how
to enforce her rights as the first occupant.

For the summer Resin-bee, A. bellicosum, the conditions are very
different. At the moment when the Osmia is building, she is still in the
larval, or at most in the nymphal stage. Her abode, which would not be
more absolutely silent if deserted, her shell, with its vast untenanted
porch, will not tempt the earlier Resin-bee, who herself wants
apartments right at the far end of the spiral, but it might suit the
Osmia, who knows how to fill the shell with cells up to the mouth. The
last whorl left vacant by the Anthidium is a magnificent lodging which
nothing prevents the mason from occupying. The Osmia does seize upon
it, in fact, and does so too often for the welfare of the unfortunate
late-comer. The final resin lid takes the place, for the Osmia, of
the mud stopper with which she cuts off at the back the portion of the
spiral too narrow for her labours. Upon this lid she builds her mass of
cells in so many storeys, after which she covers the whole with a
thick defensive plug. In short, the work is conducted as though the
Snail-shell contained nothing.

When July arrives, this doubly-tenanted house becomes the scene of a
tragic conflict. Those below, on attaining the adult state, burst their
swaddling-bands, demolish their resin partitions, pass through the
gravel barricade and try to release themselves; those above, larvae
still or budding pupae, prisoners in their shells until the following
spring, completely block the way. To force a passage from the far-end
of those catacombs is beyond the strength of the Resin-bee, already
weakened by the effort of breaking out of her own nest. A few of the
Osmia's partitions are damaged, a few cocoons receive slight injuries;
and then, worn out with vain struggles, the captives abandon hope and
perish behind the impregnable wall of earth. And with them perish also
certain parasites, even less fit for the prodigious work of clearance:
Zonites and Chryses (Chrysis flammea), of whom the first are consumers
of provisions and the second of grubs.

This lamentable ending of the Resin-bee, buried alive under the Osmia's
walls, is not a rare accident to be passed over in silence or mentioned
in a few words; on the contrary, it happens very often; and its
frequency suggests this thought: the school which sees in instinct an
acquired habit treats the slightest favourable occurrence in the course
of animal industry as the starting-point of an improvement which,
transmitted by heredity and becoming in time more and more accentuated,
at last grows into a settled characteristic common to the whole race.
There is, it is true, a total absence of positive proofs in support of
this theory; but it is stated with a wealth of hypothesis that leaves
a thousand loopholes: 'Granting that...Supposing that...It may
be...nothing need prevent us from believing... It is quite possible...'
Thus argued the master; and the disciples have not yet hit upon anything
better.

'If the sky were to fall,' said Rabelais, 'the larks would all be
caught.'

Yes, but the sky stays up; and the larks go on flying.

'If things happened in such and such a way,' says our friend, 'instinct
may have undergone variations and modifications.'

Yes, but are you quite sure that things happened as you say?

I banish the word 'if' from my vocabulary. I suppose nothing, I take
nothing for granted; I pluck the brutal fact, the only thing that can be
trusted; I record it and then ask myself what conclusion rests upon
its solid framework. From the fact which I have related we may draw the
following inference:

'You say that any modification profitable to the animal is transmitted
throughout a series of favoured ones who, better equipped with tools,
better endowed with aptitudes, abandon the ancient usages and replace
the primitive species, the victim of the struggle for life. You declare
that once, in the dim distance of the ages, a Bee found herself by
accident in possession of a dead Snail-shell. The safe and peaceful
lodging pleased her fancy. On and on went the hereditary liking; and the
Snail-shell proved more and more agreeable to the insect's descendants,
who began to look for it under the stones, so that later generations,
with the aid of habit, ended by adopting it as the ancestral dwelling.
Again by accident, the Bee happened upon a drop of resin. It was soft,
plastic, well-suited for the partitioning of the Snail-shell; it soon
hardened into a solid ceiling. The Bee tried the resinous gum and
benefited by it. Her successors also benefited by it, especially after
improving it. Little by little, the rubble-work of the lid and of the
gravel barricade was invented: an enormous improvement, of which the
race did not fail to take advantage. The defensive fortification was the
finishing-touch to the original structure. Here we have the origin and
development of the instinct of the Resin-bees who make their home in
Snail-shells.'

This glorious genesis of insect ways and means lacks just one little
thing: probability. Life everywhere, even among the humble, has two
phases: its share of good and its share of evil. Avoiding the latter
and seeking the former is the rough balance-sheet of life's actions.
Animals, like ourselves, have their portion of the sweet and the bitter:
they are just as anxious to reduce the second as to increase the first;
for, with them as with us,

     De malheurs evites le bonheur se compose.
     (Bad luck missed is good luck gained.)

If the Bee has so faithfully handed down her casual invention of a resin
nest built inside a Snail-shell, then there is no denying that she must
have just as faithfully handed down the means of averting the terrible
danger of belated hatchings. A few mothers, escaping at rare intervals
from the catacombs blocked by the Osmiae, must have retained a lively
memory, a powerful impression of their desperate struggle through the
mass of earth; they must have inspired their descendants with a dread
of those vast dwellings where the stranger comes afterwards and builds;
they must have taught them by habit the means of safety, the use of the
medium-sized shell, which the nest fills to the mouth. So far as the
prosperity of the race was concerned, the discontinuance of the system
of empty vestibules was far more important than the invention of the
barricade, which is not altogether indispensable: it would have saved
them from perishing miserably, behind impenetrable walls, and would have
considerably increased the numbers of their posterity.

Thousands and thousands of experiments have been made throughout the
ages with Snail-shells of average dimensions: the thing is certain,
because I find many of them to-day. Well, have these life-saving
experiments, with their immense importance to the race, become general
by hereditary bequest? Not at all: the Resin-bee persists in using big
Snail-shells just as though her ancestors had never known the danger of
the Osmia-blocked vestibule. Once these facts are duly recognized, the
conclusion is irresistible: it is obvious that, as the insect does not
hand down the casual modification tending towards the avoidance of
what is to its disadvantage, neither does it hand down the modification
leading to the adoption of what is to its advantage. However lively the
impression made upon the mother, the accidental leaves no trace in the
offspring. Chance plays no part in the genesis of the instincts.

Next to these tenants of the Snail-shells we have two other Resin-bees
who never come to the shells for a cabin for their nests. They are
Anthidium quadrilobum, LEP., and A. Latreillii, LEP., both exceedingly
uncommon in my district. If we meet them very rarely, however, this may
well be due to the difficulty of seeing them; for they lead extremely
solitary and wary lives. A warm nook under some stone or other; the
deserted streets of an Ant-hill in a sun-baked bank; a Beetle's vacant
burrow a few inches below the ground; in short, a cavity of some
sort, perhaps arranged by the Bee's own care: these are the only
establishments which I know them to occupy. And here, with no other
shelter than the cover of the refuge, they build a mass of cells joined
together and grouped into a sphere, which, in the case of the Four-lobed
Resin-bee, attains the size of a man's fist and, in that of Latreille's
Resin-bee, the size of a small apple.

At first sight, we remain very uncertain as to the nature of the strange
ball. It is brown, rather hard, slightly sticky, with a bituminous
smell. Outside are encrusted a few bits of gravel, particles of earth,
heads of large-sized Ants. This cannibal trophy is not a sign of
barbarous customs: the Bee does not decapitate Ants to adorn her hut.
An inlayer, like her colleagues of the Snail-shell, she gathers any hard
granule near at hand capable of strengthening her work; and the dried
skulls of Ants, which are frequent around about her abode, are in her
eyes building-stones of equal value to the pebbles. One and all employ
whatever they can find without much seeking. The inhabitant of the
shell, in order to construct her barricade, makes shift with the dry
excrement of the nearest Snail; the denizen of the flat stones and of
the roadside banks frequented by the Ants does what she can with the
heads of the defunct and, should these be lacking, is ready to replace
them with something else. Moreover, the defensive inlaying is slight;
we see that the insect attaches no great importance to it and has every
confidence in the stout wall of the home.

The material of which the work is made at first suggests some rustic
wax, much coarser than that of the Bumble-bees, or rather some tar
of unknown origin. We think again and then recognize in the puzzling
substance the semitransparent fracture, the quality of becoming soft
when exposed to heat and of burning with a smoky flame, the solubility
in spirits of wine--in short, all the distinguishing characteristics
of resin. Here then are two more collectors of the exudations of the
Coniferae. At the points where I find their nests are Aleppo pines,
cypresses, brown-berried junipers and common junipers. Which of the four
supplies the mastic? There is nothing to tell us. Nor is there anything
to explain how the native amber-colour of the resin is replaced in the
work of both Bees by a dark-brown hue resembling that of pitch. Does the
insect collect resin impaired by the weather, soiled by the sanies of
rotten wood? When kneading it, does it mix some dark ingredient with it?
I look upon this as possible, but not as proved, since I have never seen
the Bee collecting her resin.

While this point escapes me, another of higher interest appears most
plainly; and that is the large amount of resinous material used in a
single nest, especially in that of Anthidium quadrilobum, in which I
have counted as many as twelve cells. The nest of the Mason-bee of
the Pebbles is hardly more massive. For so costly an establishment,
therefore, the Resin-bee collects her pitch on the dead pine as
copiously as the Mason-bee collects her mortar on the macadamized
road. Her workshop no longer shows us the niggardly partitioning of a
Snail-shell with two or three drops of resin; what we see is the whole
building of the house, from the basement to the roof, from the thick
outer walls to the partitions of the rooms. The cement expended would
be enough to divide hundreds of Snail-shells, wherefore the title of
Resin-bee is due first and foremost to this master-builder in pitch.
Honourable mention should be awarded to A. Latreillii, who rivals
her fellow-worker as far as her smaller stature permits. The other
manipulators of resin, those who build partitions in Snail-shells, come
third, a very long way behind.

And now, with the facts to support us, let us philosophize a little.
We have here, recognized as of excellent standard by all the expert
classifiers, so fastidious in the arrangement of their lists, a generic
group, called Anthidium, containing two guilds of workers entirely
dissimilar in character: the cotton-fullers and the resin-kneaders. It
is even possible that other species, when their habits are better known,
will come and increase this variety of manufactures. I confine myself to
the little that I know and ask myself in what the manipulator of cotton
differs from the manipulator of resin as regards tools, that is to
say, organs. Certainly, when the genus Anthidium was set down by
the classifiers, they were not wanting in scientific precision: they
consulted, under the lens of the microscope, the wings, the mandibles,
the legs, the harvesting-brush, in short, all the details calculated
to assist the proper delimitation of the group. After this minute
examination by the experts, if no organic differences stand revealed,
the reason is that they do not exist. Any dissimilarity of structure
could not escape the accurate eyes of our learned taxonomists. The
genus, therefore, is indeed organically homogeneous; but industrially it
is thoroughly heterogeneous. The implements are the same and the work is
different.

That eminent Bordeaux entomologist, Professor Jean Perez, to whom I
communicated the misgivings aroused in my mind by the contradictory
nature of my discoveries, thinks that he has found the solution of the
difficulty in the conformation of the mandibles. I extract the following
passage from his volume, "Les Abeilles":

'The cotton-pressing females have the edge of their mandibles cut out
into five or six little teeth, which make an instrument admirably suited
for scraping and removing the hairs from the epidermis of the plants. It
is a sort of comb or teasel. The resin-kneading females have the edge of
the mandible not toothed, but simply curved; the tip alone, preceded
by a notch which is pretty clearly marked in some species, forms a real
tooth; but this tooth is blunt and does not project. The mandible, in
short, is a kind of spoon perfectly fitted to remove the sticky matter
and to shape it into a ball.'

Nothing better could be said to explain the two sorts of industry: in
the one case, a rake which gathers the wool; in the other, a spoon
which scoops up the resin. I should have left it at that and felt quite
content without further investigation, if I had not had the curiosity to
open my boxes and, in my turn, to take a good look, side by side, at
the workers in cement and the workers in cotton. Allow me, my learned
master, to whisper in your ear what I saw.

The first that I examine is Anthidium septemdentatum. A spoon: yes, it
is just that. Powerful mandibles, shaped like an isosceles triangle,
flat above, hollowed out below; and no indentations, none whatsoever.
A splendid tool, as you say, for gathering the viscous pellet; quite as
efficacious in its kind of work as is the rake of the toothed mandibles
for gathering cotton. Here certainly is a creature potently-gifted, even
though it be for a poor little task, the scooping up of two or three
drops of glue.

Things are not quite so satisfactory with the second Resin-bee of the
Snail-shells, A. bellicosum. I find that she has three teeth to her
mandibles. Still, they are slight and project very little. Let us say
that this does not count, even though the work is exactly the same.
With A. quadrilobum the whole thing breaks down. She, the queen of
Resin-bees; she, who collects a lump of mastic the size of one's fist,
enough to subdivide hundreds of her kinswomen's Snail-shells: well, she,
by way of a spoon, carries a rake! On the wide edges of her mandibles
stand four teeth, as long and pointed as those of the most zealous
cotton-gleaner. A. florentinum, that mighty manufacturer of
cotton-goods, can hardly rival her in respect of combing-tools. And
nevertheless, with her toothed implement, a sort of saw, the Resin-bee
collects her great heap of pitch, load by load; and the material is
carried not rigid, but sticky, half-fluid, so that it may amalgamate
with the previous lots and be fashioned into cells.

A. Latreillii, without having a very large implement, also bears witness
to the possibility of heaping up soft resin with a rake; she arms her
mandibles with three or four sharply-cut teeth. In short, out of four
Resin-bees, the only four that I know, one is armed with a spoon, if
this expression be really suited to the tool's function; the three
others are armed with a rake; and it so happens that the most copious
heap of resin is just the work of the rake with the most teeth to it,
a tool suited to the cotton-reapers, according to the views of the
Bordeaux entomological expert.

No, the explanation that appealed to me so much at first is not
admissible. The mandible, whether supplied with teeth or not, does not
account at all for the two manufactures. May we, in this predicament,
have recourse to the general structure of the insect, although this is
not distinctive enough to be of much use to us? Not so either; for,
in the same stone-heaps where the Osmia and the two Resin-bees of the
Snail-shells work, I find from time to time another manipulator of
mastic who bears no structural relationship whatever to the genus
Anthidium. It is a small-sized Mason-wasp, Odynerus alpestris, SAUSS.
She builds a very pretty nest with resin and gravel in the shells of
the young Common Snail, of Helix nemoralis and sometimes of Bulimulus
radiatus. I will describe her masterpiece on some other occasion. To
one acquainted with the genus Odynerus, any comparison with the Anthidia
would be an inexcusable error. In larval diet, in shape, in habits, they
form two dissimilar groups, very far removed one from the other. The
Anthidia feed their offspring on honey-bread; the Odyneri feed it on
live prey. Well, with her slender form, her weakly frame, in which
the most clear-seeing eye would seek in vain for a clue to the trade
practised, the Alpine Odynerus, the game-lover, uses pitch in the same
way as the stout and massive Resin-bee, the honey-lover. She even uses
it better, for her mosaic of tiny pebbles is much prettier than the
Bee's and no less solid. With her mandibles, this time neither spoon nor
rake, but rather a long forceps slightly notched at the tip, she gathers
her drop of sticky matter as dexterously as do her rivals with their
very different outfit. Her case will, I think, persuade us that neither
the shape of the tool nor the shape of the worker can explain the work
done.

I will go further: I ask myself in vain the reason of this or that trade
in the case of a fixed species. The Osmiae make their partitions with
mud or with a paste of chewed leaves; the Mason-bees build with cement;
the Pelopaeus-wasps fashion clay pots; the Megachiles made disks
cut from leaves into urns; the Anthidia felt cotton into purses;
the Resin-bees cement together little bits of gravel with gum; the
Carpenter-bees and the Lithurgi bore holes in timber; the Anthophorae
tunnel the roadside slopes. Why all these different trades, to say
nothing of the others? How are they prescribed for the insect, this one
rather than that?

I foresee the answer: they are prescribed by the organization. An insect
excellently equipped for gathering and felting cotton is ill-equipped
for cutting leaves, kneading mud or mixing resin. The tool in its
possession decides its trade.

This is a very simple explanation, I admit, and one within the scope
of everybody: in itself a sufficient recommendation for any one who
has neither the inclination nor the time to undertake a more thorough
investigation. The popularity of certain speculative views is due
entirely to the easy food which they provide for our curiosity. They
save us much long and often irksome study; they impart a veneer of
general knowledge. There is nothing that achieves such immediate success
as an explanation of the riddle of the universe in a word or two. The
thinker does not travel so fast: content to know little so that he may
know something, he limits his field of search and is satisfied with
a scanty harvest, provided that the grain be of good quality. Before
agreeing that the tool determines the trade, he wants to see things with
his own eyes; and what he observes is far from confirming the sweeping
statement. Let us share his doubts for a moment and look into matters
more closely.

Franklin left us a maxim which is much to the point here. He said that a
good workman should be able to plane with a saw and to saw with a plane.
The insect is too good a workman not to follow the advice of the sage
of Boston. Its industry abounds in instances where the plane takes the
place of the saw, or the saw of the plane; its dexterity makes good the
inadequacy of the implement. To go no further, have we not just seen
different artisans collecting and using pitch, some with spoons, others
with rakes, others again with pincers? Therefore, with such equipment
as it possesses, the insect would be capable of abandoning cotton for
leaves, leaves for resin, resin for mortar, if some predisposition of
talent did not make it keep to its speciality.

These few lines, which are the outcome not of a heedless pen but of
mature reflection, will set people talking of hateful paradoxes. We
will let them talk and we will submit the following proposition to our
adversaries: take an entomologist of the highest merit, a Latreille
(Pierre Andre Latreille (1762-1833), one of the founders of modern
entomological science.--Translator's Note.), for instance, versed in all
the details of the structure of insects but utterly unacquainted with
their habits. He knows the dead insect better than anybody, but he has
never occupied himself with the living insect. As a classifier, he is
beyond compare; and that is all. We ask him to examine a Bee, the first
that comes to hand, and to name her trade from her tools.

Come, be honest: could he? Who would dare put him to such a test? Has
personal experience not fully convinced us that the mere examination
of the insect can tell us nothing about its particular industry? The
baskets on its legs and the brush on its abdomen will certainly inform
us that it collects honey and pollen; but its special art will remain an
utter secret, notwithstanding all the scrutiny of the microscope. In our
own industries, the plane denotes the joiner, the trowel the mason, the
scissors the tailor, the needle the seamstress. Are things the same
in animal industry? Just show us, if you please, the trowel that is
a certain sign of the mason-insect, the chisel that is a positive
characteristic of the carpenter-insect, the iron that is an authentic
mark of the pinking-insect; and as you show them, say:

'This one cuts leaves; that one bores wood; that other mixes cement.'

And so on, specifying the trade from the tool.

You cannot do it, no one can; the worker's speciality remains an
impenetrable secret until direct observation intervenes. Does not
this incapacity, even of the most expert, proclaim loudly that animal
industry, in its infinite variety, is due to other causes besides the
possession of tools? Certainly, each of those specialists requires
implements; but they are rough and ready implements, good for all sorts
of purposes, like the tool of Franklin's workman. The same notched
mandible that reaps cotton, cuts leaves and moulds pitch also kneads
mud, scrapes decayed wood and mixes mortar; the same tarsus that
manufactures cotton and disks cut out of leaves is no less clever at the
art of making earthen partitions, clay turrets and gravel mosaics.

What then is the reason of these thousand industries? In the light of
facts, I can see but one: imagination governing matter. A primordial
inspiration, a talent antecedent to the actual form, directs the tool
instead of being subordinate to it. The instrument does not determine
the manner of industry; the tool does not make the workman. At the
beginning there is an object, a plan, in view of which the animal acts,
unconsciously. Have we eyes to see with, or do we see because we have
eyes? Does the function create the organ, or the organ the function? Of
the two alternatives, the insect proclaims the first. It says:

'My industry is not imposed upon me by the implement which I possess;
what I do is to use the implement, such as it is, for the talent with
which I am gifted.'

It says to us, in its own way:

'The function has determined the organ; vision is the reason of the
eye.'

In short, it repeats to us Virgil's profound reflection:

'Mens agitat molem'; 'Mind moves matter.'




CHAPTER 11. THE POISON OF THE BEE.

I have discussed elsewhere the stings administered by the Wasps to
their prey. Now chemistry comes and puts a spoke in the wheel of our
arguments, telling us that the poison of the Bees is not the same as
that of the Wasps. The Bees' is complex and formed of two elements, acid
and alkaline. The Wasps' possess only the acid element; and it is to
this very acidity and not to the 'so-called' skill of the operators that
the preservation of the provisions is due. (The author's numerous essays
on the Wasps will form the contents of later works. In the meantime, cf.
"Insect Life," by J.H. Fabre, translated by the author of "Mademoiselle
Mori": chapters 4 to 12, and 14 to 18; and "The Life and Love of the
Insect," by J. Henri Fabre, translated by Alexander Teixeira de Mattos:
chapters 11, 12 and 17.--Translator's Note.)

Admitting that there is a difference in the nature of the venom, I fail
to see that this has any bearing on the problem in hand. I can inoculate
with various liquids--acids, weak nitric acid, alkalis, ammonia, neutral
bodies, spirits of wine, essence of turpentine--and obtain conditions
similar to those of the victims of the predatory insects, that is to
say, inertia with the persistence of a dull vitality betrayed by
the movements of the mouth-parts and antennae. I am not, of course,
invariably successful, for there is neither delicacy nor precision in
my poisoned needle and the wound which it makes does not bear comparison
with the tiny puncture of the unerring natural sting; but, after all,
it is repeated often enough to put the object of my experiment beyond
doubt. I should add that, to achieve success, we must have a subject
with a concentrated ganglionic column, such as the Weevil, the
Buprestis, the Dung-beetle and others. Paralysis is then obtained with
but a single prick, made at the point which the Cerceris has revealed
to us, the point at which the corselet joins the rest of the thorax. In
that case, the least possible quantity of the acrid liquid is instilled,
a quantity too small to endanger the patient's life. With scattered
nervous centres, each requiring a separate operation, this method is
impracticable: the victim would die of the excess of corrosive fluid. I
am quite ashamed to have to recall these old experiments. Had they been
resumed and carried on by others of greater authority than I, we should
have escaped the objections of chemistry.

When light is so easy to obtain, why go in search of scientific
obscurity? Why talk of acid or alkaline reactions, which prove nothing,
when it is so simple to have recourse to facts, which prove everything?
Before declaring that the hunting insects' poison has preservative
properties merely because of its acid qualities, it would have been well
to enquire if the sting of a Bee, with its acid and its alkali, could
not perchance produce the same effects as that of the paralyser, whose
skill is categorically denied. The chemists never gave this a thought.
Simplicity is not always welcome in our laboratories. It is my duty to
repair that little omission. I propose to enquire if the poison of the
Bee, the chief of the Apidae, is suitable for a surgery that paralyses
without killing.

The enquiry bristles with difficulties, though this is no reason for
abandoning it. First and foremost, I cannot possibly operate with the
Bee just as I catch her. Time after time I make the attempt, without
once succeeding; and patience becomes exhausted. The sting has to
penetrate at a definite point, exactly where the Wasp's sting would
have entered. My intractable captive tosses about angrily and stings at
random, never where I wish. My fingers get hurt even oftener than the
patient. I have only one means of gaining a little control over the
indomitable dart; and that is to cut off the Bee's abdomen with my
scissors, to seize the stump instantly with a fine forceps and to apply
the tip at the spot where the sting is to enter.

Everybody knows that the Bee's abdomen needs no orders from the head
to go on drawing its weapon for a few instants longer and to avenge
the deceased before being itself overcome with death's inertia. This
vindictive persistency serves me to perfection. There is another
circumstance in my favour: the barbed sting remains where it is, which
enables me to ascertain the exact spot pierced. A needle withdrawn
as soon as inserted would leave me doubtful. I can also, when the
transparency of the tissues permits, perceive the direction of the
weapon, whether perpendicular and favourable to my plans, or slanting
and therefore valueless. Those are the advantages.

The disadvantages are these: the amputated abdomen, though more
tractable than the entire Bee, is still far from satisfying my wishes.
It gives capricious starts and unexpected pricks. I want it to sting
here. No, it balks my forceps and goes and stings elsewhere: not very
far away, I admit; but it takes so little to miss the nerve-centre which
we wish to get at. I want it to go in perpendicularly. No, in the
great majority of cases it enters obliquely and passes only through the
epidermis. This is enough to show how many failures are needed to make
one success.

Nor is this all. I shall be telling nobody anything new when I recall
the fact that the Bee's sting is very painful. That of the hunting
insects, on the contrary, is in most cases insignificant. My skin, which
is no less sensitive than another's, pays no attention to it: I handle
Sphex, Ammophilae and Scoliae without heeding their lancet-pricks. I
have said this before; I remind the reader of it because of the matter
in hand. In the absence of well-known chemical or other properties, we
have really but one means of comparing the two respective poisons; and
that is the amount of pain produced. All the rest is mystery. Besides,
no poison, not even that of the Rattlesnake, has hitherto revealed the
cause of its dread effects.

Acting, therefore, under the instruction of that one guide, pain, I
place the Bee's sting far above that of the predatory insects as an
offensive weapon. A single one of its thrusts must equal and often
surpass in efficaciousness the repeated wounds of the other. For all
these reasons--an excessive display of energy; the variable quantity of
the virus inoculated by a wriggling abdomen which no longer measures the
emission by doses; a sting which I cannot direct as I please; a wound
which may be deep or superficial, the weapon entering perpendicularly or
obliquely, touching the nerve-centres or affecting only the surrounding
tissues--my experiments ought to produce the most varied results.

I obtain, in fact, every possible kind of disorder: ataxy, temporary
disablement, permanent disablement, complete paralysis, partial
paralysis. Some of my stricken victims recover; others die after a brief
interval. It would be an unnecessary waste of space to record in this
volume my hundred and one attempts. The details would form tedious
reading and be of very little advantage, as in this sort of study it
is impossible to marshal one's facts with any regularity. I will,
therefore, sum them up in a few examples.

A colossal member of the Grasshopper tribe, the most powerful in my
district, Decticus verrucivorus (This Decticus has received its specific
name of verrucivorus, or Wart-eating, because it is employed by
the peasants in Sweden and elsewhere to bite off the warts on their
fingers.--Translator's Note.), is pricked at the base of the neck, on
the line of the fore-legs, at the median point. The prick goes straight
down. The spot is the same as that pierced by the sting of the slayer
of Crickets and Ephippigers. (A species of Green Grasshopper. The Sphex
paralyses Crickets and Grasshoppers to provide food for her grubs. Cf.
"Insect Life": chapters 6 to 12.--Translator's Note.) The giantess, as
soon as stung, kicks furiously, flounders about, falls on her side and
is unable to get up again. The fore-legs are paralysed; the others are
capable of moving. Lying sideways, if not interfered with, the insect in
a few moments gives no signs of life beyond a fluttering of the antennae
and palpi, a pulsation of the abdomen and a convulsive uplifting of the
ovipositor; but, if irritated with a slight touch, it stirs its four
hind-legs, especially the third pair, those with the big thighs, which
kick vigorously. Next day, the condition is much the same, with an
aggravation of the paralysis, which has now attacked the middle-legs.
On the day after that, the legs do not move, but the antennae, the palpi
and the ovipositor continue to flutter actively. This is the condition
of the Ephippiger stabbed three times in the thorax by the Languedocian
Sphex. One point alone is missing, a most important point: the long
persistence of a remnant of life. In fact, on the fourth day, the
Decticus is dead; her dark colour tells me so.

There are two conclusions to be drawn from this experiment and it is
well to emphasise them. First, the Bee's poison is so active that a
single dagger-thrust aimed at a nervous centre kills in four days one
of the largest of the Orthoptera (An order of insects including the
Grasshoppers, Locusts, Cockroaches, Mantes and Earwigs, in addition
to the Stick- and Leaf-insects, Termites, Dragon-flies, May-flies,
Book-lice and others.--Translator's Note.), though an insect of powerful
constitution. Secondly, the paralysis at first affects only the legs
whose ganglion is attacked; next, it spreads slowly to the second
pair; lastly, it reaches the third. The local effect is diffused. This
diffusion, which might well take place in the victims of the predatory
insects, plays no part in the latters' method of operation. The egg,
which will be laid immediately afterwards, demands the complete inertia
of the prey from the outset. Hence all the nerve-centres that govern
locomotion must be numbed instantaneously by the virus.

I can now understand why the poison of the predatory Wasps is
comparatively painless in its effects. If it possessed the strength of
that of the Bee, a single stab would impair the vitality of the prey,
while leaving it for some days capable of violent movements that would
be very dangerous to the huntress and especially to the egg. More
moderate in its action, it is instilled at the different nervous
centres, as is the case more particularly with the caterpillars.
(Caterpillars are the prey of the Ammophila, which administers a
separate stab to each of the several ganglia.--Translator's Note.)
In this way, the requisite immobility is obtained at once; and,
notwithstanding the number of wounds, the victim is not a speedy corpse.
To the marvels of the paralysers' talent we must add one more: their
wonderful poison, the strength of which is regulated by delicate doses.
The Bee revenging herself intensifies the virulence of her poison; the
Sphex putting her grubs' provender to sleep weakens it, reduces it to
what is strictly necessary.

One more instance of nearly the same kind. I prefer to take my subjects
from among the Orthoptera, which, owing to their imposing size and the
thinness of their skin at the points to be attacked, lend themselves
better than other insects to my delicate manipulations. The armour of
a Buprestis, the fat blubber of a Rosechafer-grub, the contortions of
a caterpillar present almost insuperable obstacles to the success of
a sting which it is not in my power to direct. The insect which I
now offer to the Bee's lancet is the Great Green Grasshopper (Locusta
viridissima), the adult female. The prick is given in the median line of
the fore-legs.

The effect is overwhelming. For two or three seconds the insect writhes
in convulsions and then falls on its side, motionless throughout,
save in the ovipositor and the antennae. Nothing stirs so long as the
creature is left alone; but, if I tickle it with a hair-pencil, the four
hind-legs move sharply and grip the point. As for the fore-legs, smitten
in their nerve-centre, they are quite lifeless. The same condition
is maintained for three days longer. On the fifth day, the creeping
paralysis leaves nothing free but the antennae waving to and fro and
the abdomen throbbing and lifting up the ovipositor. On the sixth, the
Grasshopper begins to turn brown; she is dead. Except that the vestige
of life is more persistent, the case is the same as that of the
Decticus. If we can prolong the duration, we shall have the victim of
the Sphex.

But first let us look into the effect of a prick administered elsewhere
than opposite the thoracic ganglia. I cause a female Ephippiger to be
stung in the abdomen, about the middle of the lower surface. The patient
does not seem to trouble greatly about her wound: she clambers gallantly
up the sides of the bell-jar under which I have placed her; she goes on
hopping as before. Better still, she sets about browsing the vine-leaf
which I have given her for her consolation. A few hours pass and the
whole thing is forgotten. She has made a rapid and complete recovery.

A second is wounded in three places on the abdomen: in the middle and on
either side. On the first day, the insect seems to have felt nothing;
I see no sign of stiffness in its movements. No doubt it is suffering
acutely; but these stoics keep their troubles to themselves. Next day,
the Ephippiger drags her legs a little and walks somewhat slowly. Two
days more; and, when laid on her back, she is unable to turn over. On
the fifth day, she succumbs. This time, I have exceeded the dose; the
shock of receiving three stabs was too much for her.

And so with the others, down to the sensitive Cricket, who, pricked once
in the abdomen, recovers in one day from the painful experience and goes
back to her lettuce-leaf. But, if the wound is repeated a few times,
death ensues within a more or less short period. I make an
exception, among those who pay tribute to my cruel curiosity, of the
Rosechafer-grubs, who defy three and four needle-thrusts. They will
collapse suddenly and lie outstretched, flabby and lifeless; and, just
when I am thinking them dead or paralysed, the hardy creatures will
recover consciousness, move along on their backs (This is the usual mode
of progression of the Cetonia- or Rosechafer-grub. Cf. "The Life and
Love of the Insect": chapter 11.--Translator's Note.), bury themselves
in the mould. I can obtain no precise information from them. True, their
thinly scattered cilia and their breastplate of fat form a palisade and
a rampart against the sting, which nearly always enters only a little
way and that obliquely.

Let us leave these unmanageable ones and keep to the Orthoperon, which
is more amenable to experiment. A dagger-thrust, we were saying, kills
it if directed upon the ganglia of the thorax; it throws it into a
transient state of discomfort if directed upon another point. It is,
therefore, by its direct action upon the nervous centres that the poison
reveals its formidable properties.

To generalize and say that death is always near at hand when the sting
is administered in the thoracic ganglia would be going too far: it
occurs frequently, but there are a good many exceptions, resulting from
circumstances impossible to define. I cannot control the direction of
the sting, the depth attained, the quantity of poison shed; and the
stump of the Bee is very far from making up for my shortcomings. We have
here not the cunning sword-play of the predatory insect, but a casual
blow, ill-placed and ill-regulated. Any accident is possible, therefore,
from the gravest to the mildest. Let us mention some of the more
interesting.

An adult Praying Mantis (Mantis religiosa, so-called because the toothed
fore-legs, in which it catches and kills its prey, adopt, when folded,
an attitude resembling that of prayer.--Translator's Note.) is pricked
level with the attachment of the predatory legs. Had the wound been in
the centre, I should have witnessed an occurrence which, although I have
seen it many times, still arouses my liveliest emotion and surprise.
This is the sudden paralysis of the warrior's savage harpoons. No
machinery stops more abruptly when the mainspring breaks. As a rule, the
inertia of the predatory legs attacks the others in the course of a day
or two; and the palsied one dies in less than a week. But the present
sting is not in the exact centre. The dart has entered near the base
of the right leg, at less than a millimetre (.039 inch.--Translator's
Note.) from the median point. That leg is paralysed at once; the other
is not; and the insect employs it to the detriment of my unsuspecting
fingers, which are pricked to bleeding-point by the spike at the
tip. Not until to-morrow is the leg which wounded me to-day rendered
motionless. This time, the paralysis goes no farther. The Mantis
moves along quite well, with her corselet proudly raised, in her usual
attitude; but the predatory fore-arms, instead of being folded against
the chest, ready for attack, hang lifeless and open. I keep the cripple
for twelve days longer, during which she refuses all nourishment, being
incapable of using her tongs to seize the prey and lift it to her mouth.
The prolonged abstinence kills her.

Some suffer from locomotor ataxy. My notes recall an Ephippiger who,
pricked in the prothorax away from the median line, retained the use
of her six limbs without being able to walk or climb for lack of
co-ordination in her movements. A singular awkwardness left her wavering
between going back and going forward, between turning to the right and
turning to the left.

Some are smitten with semiparalysis. A Cetonia-grub, pricked away from
the centre on a level with the fore-legs, has her right side flaccid,
spread out, incapable of contracting, while the left side swells,
wrinkles and contracts. Since the left half no longer receives the
symmetrical cooperation of the right half, the grub, instead of curling
into the normal volute, closes its spiral on one side and leaves it wide
open on the other. The concentration of the nervous apparatus, poisoned
by the venom down one side of the body only, a longitudinal half,
explains this condition, which is the most remarkable of all.

There is nothing to be gained by multiplying these examples. We have
seen pretty clearly the great variety of results produced by the
haphazard sting of a Bee's abdomen; let us now come to the crux of the
matter. Can the Bee's poison reduce the prey to the condition required
by the predatory Wasp? Yes, I have proved it by experiment; but the
proof calls for so much patience that it seemed to me to suffice when
obtained once for each species. In such difficult conditions, with a
poison of excessive strength, a single success is conclusive proof; the
thing is possible so long as it occurs once.

A female Ephippiger is stung at the median point, just a little in front
of the fore-legs. Convulsive movements lasting for a few seconds
are followed by a fall to one side, with pulsations of the abdomen,
flutterings of the antennae and a few feeble movements of the legs. The
tarsi cling firmly to the hair-pencil which I hold out to them. I place
the insect on its back. It lies motionless. Its state is absolutely the
same as that to which the Languedocian Sphex (Cf. "Insect Life": chapter
10.--Translator's Note.) reduces her Ephippigers. For three weeks on
end, I see repeated in all its details the spectacle to which I have
been accustomed in the victims extracted from the burrows or taken from
the huntress: the wide-open mandibles, the quivering palpi and tarsi,
the ovipositor shuddering convulsively, the abdomen throbbing at long
intervals, the spark of life rekindled at the touch of a pencil. In
the fourth week, these signs of life, which have gradually weakened,
disappear, but the insect still remains irreproachably fresh. At last
a month passes; and the paralysed creature begins to turn brown. It is
over; death has come.

I have the same success with a Cricket and also with a Praying Mantis.
In all three cases, from the point of view of long-maintained freshness
and of the signs of life proved by slight movements, the resemblance
between my victim and those of the predatory insects is so great that no
Sphex and no Tachytes would have disowned the product of my devices. My
Cricket, my Ephippiger, my Mantis had the same freshness as theirs; they
preserved it as theirs did for a period amply sufficient to allow of
the grubs' complete evolution. They proved to me, in the most conclusive
manner, they prove to all whom it may interest, that the poison of the
Bees, leaving its hideous violence on one side, does not differ in its
effects from the poison of the predatory Wasps. Are they alkaline or
acid? The question is an idle one in this connection. Both of them
intoxicate, derange, torpify the nervous centres and thus produce either
death or paralysis, according to the method of inoculation. For the
moment, that is all. No one is yet able to say the last word on the
actions of those poisons, so terrible in infinitesimal doses. But on the
point under discussion we need no longer be ignorant: the Wasp owes the
preservation of her grub's provisions not to any special qualities of
her poison but to the extreme precision of her surgery.

A last and more plausible objection is that raised by Darwin when he
said that there were no fossil remains of instincts. And, if there were,
O master, what would they teach us? Not very much more than what we
learn from the instincts of to-day. Does not the geologist make the
erstwhile carcases live anew in our minds in the light of the world as
we see it? With nothing but analogy to guide them, he describes how
some saurian lived in the jurassic age; there are no fossil remains of
habits, but nevertheless he can tell us plenty about them, things worthy
of credence, because the present teaches him the past. Let us do a
little as he does.

I will suppose a precursor of the Calicurgi (The Calicurgus, or
Pompilus, is a Hunting Wasp, feeding her larvae on Spiders. Cf. "The
Life and Love of the Insect": chapter 12.--Translator's Note.) dwelling
in the prehistoric coal-forests. Her prey was some hideous Scorpion,
that first-born of the Arachnida. How did the Hymenopteron master the
terrible prey? Analogy tells us, by the methods of the present slayer of
Tarantulae. It disarmed the adversary; it paralysed the venomous sting
by a stroke administered at a point which we could determine for certain
by the animal's anatomy. Unless this was the way it happened, the
assailant must have perished, first stabbed and then devoured by the
prey. There is no getting away from it: either the precursor of the
Calicurgi, that slaughterer of Scorpions, knew her trade thoroughly, or
else the continuation of her race became impossible, even as it would
be impossible to keep up the race of the Tarantula-killer without the
dagger-thrust that paralyses the Spider's poison-fangs. The first who,
greatly daring, pinked the Scorpion of the coal-seams was already an
expert fencer; the first to come to grips with the Tarantula had an
unerring knowledge of her dangerous surgery. The least hesitation, the
slightest speculation; and they were lost. The first teacher would also
have been the last, with no disciples to take up her work and perfect
it.

But fossil instincts, they insist, would show us intermediary stages,
first, second and third rungs; they would show us the gradual passing
from the casual and very incorrect attempt to the perfect practice, the
fruit of the ages; with their accidental differences, they would give
us terms of comparison wherewith to trace matters from the simple to the
complex. Never mind about that, my masters: if you want varied instincts
in which to seek the source of the complex by means of the simple, it
is not necessary to search the foliations of the coal-seams and the
successive layers of the rocks, those archives of the prehistoric world;
the present day affords to contemplation an inexhaustible treasury
realizing perhaps everything that can emerge from the limbo of
possibility. In what will soon be half a century of study, I have caught
but a tiny glimpse of a very tiny corner of the realm of instinct; and
the harvest gathered overwhelms me with its variety: I do not yet know
two species of predatory Wasps whose methods are exactly the same.

One gives a single stroke of the dagger, a second two, a third three, a
fourth nine or ten. One stabs here and the other there; and neither
is imitated by the next, who attacks elsewhere. This one injures the
cephalic centres and produces death; that one respects them and produces
paralysis. Some squeeze the cervical ganglia to obtain a temporary
torpor; others know nothing of the effects of compressing the brain. A
few make the prey disgorge, lest its honey should poison the offspring;
the majority do not resort to preventive manipulations. Here are some
that first disarm the foe, who carries poisoned daggers; yonder are
others and more numerous, who have no precautions to take before
murdering the unarmed prey. In the preliminary struggle, I know some who
grab their victims by the neck, by the rostrum, by the antennae, by the
caudal threads; I know some who throw them on their backs, some who
lift them breast to breast, some who operate on them in the vertical
position, some who attack them lengthwise and crosswise, some who climb
on their backs or on their abdomens, some who press on their backs to
force out a pectoral fissure, some who open their desperately contracted
coil, using the tip of the abdomen as a wedge. And so I could go on
indefinitely: every method of fencing is employed. What could I not also
say about the egg, slung pendulum-fashion by a thread from the ceiling,
when the live provisions are wriggling underneath; laid on a scanty
mouthful, a solitary opening dish, when the dead prey requires renewing
from day to-day; entrusted to the last joint stored away, when the
victuals are paralysed; fixed at a precise spot, entailing the least
danger to the consumer and the game, when the corpulent prey has to be
devoured with a special art that warrants its freshness!

Well, how can this multitude of varied instincts teach us anything
about gradual transformation? Will the one and only dagger-thrust of the
Cerceris and the Scolia take us to the two thrusts of the Calicurgus, to
the three thrusts of the Sphex, to the manifold thrust of the Ammophila?
Yes, if we consider only numerical progression. One and one are two; two
and one are three: so run the figures. But is this what we want to
know? What has arithmetic to do with the case? Is not the whole problem
subordinate to a condition that cannot be translated into cyphers? As
the prey changes, the anatomy changes; and the surgeon always operates
with a complete understanding of his subject. The single dagger-thrust
is administered to ganglia collected into a common cluster; the manifold
thrusts are distributed over the scattered ganglia; of the two thrusts
of the Tarantula-huntress, one disarms and the other paralyses. And so
with the others: that is to say, the instinct is directed each time by
the secrets of the nervous organism. There is a perfect harmony between
the operation and the patient's anatomy.

The single stroke of the Scolia is no less wonderful than the repeated
strokes of the Ammophila. Each has her appointed game and each slays it
by a method as rational as any that our own science could invent. In
the presence of this consummate knowledge, which leaves us utterly
confounded, what a poor argument is that of 1 + 1 = 2! And what is that
progress by units to us? The universe is mirrored in a drop of water;
universal logic flashes into sight in a single sting.

Besides, push on the pitiful argument. One leads to two, two lead to
three. Granted without dispute. And then? We will accept the Scolia
as the pioneer, the foundress of the first principles of the art. The
simplicity of her method justifies our supposition. She learns her
trade in some way or other, by accident; she knows supremely well how
to paralyse her Cetonia-grub with a single dagger-thrust driven into
the thorax. One day, through some fortuitous circumstance, or rather
by mistake, she takes it into her head to strike two blows. As one is
enough for the Cetonia, the repetition was of no value unless there was
a change of prey. What was the new victim submitted to the butcher's
knife? Apparently, a large Spider, since the Tarantula and the Garden
Spider call for two thrusts. And the prentice Scolia, who used at first
to sting under the throat, had the skill, at her first attempt, to begin
by disarming her adversary and then to go quite low down, almost to the
end of the thorax, to strike the vital point. I am utterly incredulous
as to her success. I see her eaten up if her lancet swerves and hits the
wrong spot. Let us look impossibility boldly in the face and admit that
she succeeds. I then see the offspring, which have no recollection of
the fortunate event save through the belly--and then we are postulating
that the digestion of the carnivorous larva leaves a trace in the memory
of the honey-sipping insect--I see the offspring, I say, obliged to wait
at long intervals for that inspired double thrust and obliged to succeed
each time under pain of death for them and their descendants. To accept
this host of impossibilities exceeds all my faculties of belief. One
leads to two, no doubt; the Ssingle blow of the predatory Wasp will
never lead to the blow twice delivered.

In order to live, we all require the conditions that enable us to live:
this is a truth worthy of the famous axioms of La Palice. (Jacques de
Chabannes, Seigneur de La Palice [circa 1470-1525]), was a French captain
killed at the battle of Pavia. His soldiers made up in his honour a
ballad, two lines of which, translated, run:

Fifteen minutes before he died, He was still alive.

(Hence the French expression, une verite de La Palice, meaning an obvious
truth.--Translator's Note.)

The predatory insects live by their talent. If they do not possess it to
perfection, their race is lost. Hidden in the murk of the past ages, the
argument based upon the non-existence of fossil instinct is no better
able than the others to withstand the light of living realities; it
crumbles under the stroke of fate; it vanishes before a La Palice
platitude.




CHAPTER 12. THE HALICTI: A PARASITE.

Do you know the Halicti? Perhaps not. There is no great harm done: it is
quite possible to enjoy the few sweets of existence without knowing
the Halicti. Nevertheless, when questioned persistently, these humble
creatures with no history can tell us some very singular things; and
their acquaintance is not to be disdained if we would enlarge our ideas
upon the bewildering swarm of this world. Since we have nothing better
to do, let us look into the Halicti. They are worth the trouble.

How shall we recognize them? They are manufacturers of honey, generally
longer and slighter than the Bee of our hives. They constitute a
numerous group that varies greatly in size and colouring. Some there are
that exceed the dimensions of the Common Wasp; others might be compared
with the House-fly, or are even smaller. In the midst of this variety,
which is the despair of the novice, one characteristic remains
invariable. Every Halictus carries the clearly-written certificate of
her guild.

Examine the last ring, at the tip of the abdomen, on the dorsal surface.
If your capture be an Halictus, there will be here a smooth and shiny
line, a narrow groove along which the sting slides up and down when the
insect is on the defensive. This slide for the unsheathed weapon denotes
some member of the Halictus tribe, without distinction of size or
colour. No elsewhere, in the sting-bearing order, is this original sort
of groove in use. It is the distinctive mark, the emblem of the family.

Three Halicti will appear before you in this biographical fragment. Two
of them are my neighbours, my familiars, who rarely fail to settle each
year in the best parts of the enclosure. They occupied the ground before
I did; and I should not dream of evicting them, persuaded as I am that
they will well repay my indulgence. Their proximity, which allows me to
visit them daily at my leisure, is a piece of good luck. Let us profit
by it.

At the head of my three subjects is the Zebra Halictus (H. zebrus,
WALCK.), which is beautifully belted around her long abdomen with
alternate black and pale-russet scarves. Her slender shape, her size,
which equals that of the Common Wasp, her simple and pretty dress,
combine to make her the chief representative of the genus here.

She establishes her galleries in firm soil, where there is no danger
of landslips which would interfere with the work at nesting-time. In my
garden, the well-levelled paths, made of a mixture of tiny pebbles
and red clayey earth, suits her to perfection. Every spring she takes
possession of it, never alone, but in gangs whose number varies greatly,
amounting sometimes to as many as a hundred. In this way she founds what
may be described as small townships, each clearly marked out and distant
from the other, in which the joint possession of the site in no way
entails joint work.

Each has her home, an inviolable manor which none but the owner has
the right to enter. A sound buffeting would soon call to order any
adventuress who dared to make her way into another's dwelling. No such
indiscretion is suffered among the Halicti. Let each keep to her own
place and to herself and perfect peace will reign in this new-formed
society, made up of neighbours and not of fellow-workers.

Operations begin in April, most unobtrusively, the only sign of the
underground works being the little mounds of fresh earth. There is no
animation in the building-yards. The labourers show themselves very
seldom, so busy are they at the bottom of their pits. At moments, here
and there, the summit of a tiny mole-hill begins to totter and tumbles
down the slopes of the cone: it is a worker coming up with her armful
of rubbish and shooting it outside, without showing herself in the open.
Nothing more for the moment.

There is one precaution to be taken: the villages must be protected
against the passers-by, who might inadvertently trample them under foot.
I surround each of them with a palisade of reed-stumps. In the centre
I plant a danger-signal, a post with a paper flag. The sections of the
paths thus marked are forbidden ground; none of the household will walk
upon them.

May arrives, gay with flowers and sunshine. The navvies of April have
turned themselves into harvesters. At every moment I see them settling,
all befloured with yellow, atop of the mole-hills now turned into
craters. Let us first look into the question of the house. The
arrangement of the home will give us some useful information. A spade
and a three-pronged fork place the insect's crypts before our eyes.

A shaft as nearly vertical as possible, straight or winding according to
the exigencies of a soil rich in flinty remains, descends to a depth of
between eight and twelve inches. As it is merely a passage in which the
only thing necessary is that the Halictus should find an easy support in
coming and going, this long entrance-hall is rough and uneven. A regular
shape and a polished surface would be out of place here. These artistic
refinements are reserved for the apartments of her young. All that the
Halictus mother asks is that the passage should be easy to go up and
down, to ascend or descend in a hurry. And so she leaves it rugged. Its
width is about that of a thick lead-pencil.

Arranged one by one, horizontally and at different heights, the cells
occupy the basement of the house. They are oval cavities, three-quarters
of an inch long, dug out of the clay mass. They end in a short
bottle-neck that widens into a graceful mouth. They look like tiny
vaccine-phials laid on their sides. All of them open into the passage.

The inside of these little cells has the gloss and polish of a stucco
which our most experienced plasterers might envy. It is diapered with
faint longitudinal, diamond-shaped marks. These are the traces of the
polishing-tool that has given the last finish to the work. What can this
polisher be? None other than the tongue, that is obvious. The Halictus
has made a trowel of her tongue and licked the wall daintily and
methodically in order to polish it.

This final glazing, so exquisite in its perfection, is preceded by a
trimming-process. In the cells that are not yet stocked with provisions,
the walls are dotted with tiny dents like those in a thimble. Here we
recognize the work of the mandibles, which squeeze the clay with their
tips, compress it and purge it of any grains of sand. The result is a
milled surface whereon the polished layer will find a solid adhesive
base. This layer is obtained with a fine clay, very carefully selected
by the insect, purified, softened and then applied atom by atom, after
which the trowel of the tongue steps in, diapering and polishing, while
saliva, disgorged as needed, gives pliancy to the paste and finally
dries into a waterproof varnish.

The humidity of the subsoil, at the time of the spring showers, would
reduce the little earthen alcove to a sort of pap. The coating of saliva
is an excellent preservative against this danger. It is so delicate
that we suspect rather than see it; but its efficacy is none the less
evident. I fill a cell with water. The liquid remains in it quite well,
without any trace of infiltration.

The tiny pitcher looks as if it were varnished with galenite. The
impermeability which the potter obtains by the brutal infusion of his
mineral ingredients the Halictus achieves with the soft polisher of her
tongue moistened with saliva. Thus protected, the larva will enjoy all
the advantages of a dry berth, even in rain-soaked ground.

Should the wish seize us, it is easy to detach the waterproof film, at
least in shreds. Take the little shapeless lump in which a cell has been
excavated and put it in sufficient water to cover the bottom of it. The
whole earthy mass will soon be soaked and reduced to a mud which we are
able to sweep with the point of a hair-pencil. Let us have patience and
do our sweeping gently; and we shall be able to separate from the main
body the fragments of a sort of extremely fine satin. This transparent,
colourless material is the upholstery that keeps out the wet. The
Spider's web, if it formed a stuff and not a net, is the only thing that
could be compared with it.

The Halictus' nurseries are, as we see, structures that take much time
in the making. The insect first digs in the clayey earth a recess with
an oval curve to it. It has its mandibles for a pick-axe and its tarsi,
armed with tiny claws, for rakes. Rough though it be, this early work
presents difficulties, for the Bee has to do her excavating in a narrow
gully, where there is only just room for her to pass.

The rubbish soon becomes cumbersome. The insect collects it and then,
moving backwards, with its fore-legs closed over the load, it hoists it
up through the shaft and flings it outside, upon the mole-hill, which
rises by so much above the threshold of the burrow. Next come the dainty
finishing-touches: the milling of the wall, the application of a glaze
of better-quality clay, the assiduous polishing with the long-suffering
tongue, the waterproof coating and the jarlike mouth, a masterpiece of
pottery in which the stopping-plug will be fixed when the time comes
for locking the door of the room. And all this has to be done with
mathematical precision.

No, because of this perfection, the grubs' chambers could never be
work done casually from day to day, as the ripe eggs descend from the
ovaries. They are prepared long beforehand, during the bad weather,
at the end of March and in April, when flowers are scarce and the
temperature subject to sudden changes. This thankless period, often
cold, liable to hail-storms, is spent in making ready the home. Alone
at the bottom of her shaft, which she rarely leaves, the mother works at
her children's apartments, lavishing upon them those finishing-touches
which leisure allows. They are completed, or very nearly, when May comes
with the radiant sunshine and wealth of flowers.

We see the evidence of these long preparations in the burrows
themselves, if we inspect them before the provisions are brought. All of
them show us cells, about a dozen in number, quite finished, but still
empty. To begin by getting all the huts built is a sensible precaution:
the mother will not have to turn aside from the delicate task of
harvesting and egg-laying in order to perform rough navvy's work.

Everything is ready by May. The air is balmy; the smiling lawns are
gay with a thousand little flowers, dandelions, rock-roses, tansies
and daisies, among which the harvesting Bee rolls gleefully, covering
herself with pollen. With her crop full of honey and the brushes of her
legs befloured, the Halictus returns to her village. Flying very low,
almost level with the ground, she hesitates, with sudden turns and
bewildered movements. It seems that the weak-sighted insect finds its
way with difficulty among the cottages of its little township.

Which is its mole-hill among the many others near, all similar in
appearance? It cannot tell exactly save by the sign-board of certain
details known to itself alone. Therefore, still on the wing, tacking
from side to side, it examines the locality. The home is found at last:
the Halictus alights on the threshold of her abode and dives into it
quickly.

What happens at the bottom of the pit must be the same thing that
happens in the case of the other Wild Bees. The harvester enters a cell
backwards; she first brushes herself and drops her load of pollen; then,
turning round, she disgorges the honey in her crop upon the floury mass.
This done, the unwearied one leaves the burrow and flies away, back to
the flowers. After many journeys, the stack of provisions in the cell is
sufficient. This is the moment to bake the cake.

The mother kneads her flour, mingles it sparingly with honey. The
mixture is made into a round loaf, the size of a pea. Unlike our own
loaves, this one has the crust inside and the crumb outside. The middle
part of the roll, the ration which will be consumed last, when the grub
has acquired some strength, consists of almost nothing but dry pollen.
The Bee keeps the dainties in her crop for the outside of the loaf,
whence the feeble grub-worm is to take its first mouthfuls. Here it is
all soft crumb, a delicious sandwich with plenty of honey. The little
breakfast-roll is arranged in rings regulated according to the age of
the nurseling: first the syrupy outside and at the very end the dry
inside. Thus it is ordained by the economics of the Halictus.

An egg bent like a bow is laid upon the sphere. According to the
generally-accepted rule, it now only remains to close the
cabin. Honey-gatherers--Anthophorae, Osmiae, Mason-bees and many
others--usually first collect a sufficient stock of food and then,
having laid the egg, shut up the cell, to which they need pay no more
attention. The Halicti employ a different method. The compartments, each
with its round loaf and its egg--the tenant and his provisions--are not
closed up. As they all open into the common passage of the burrow, the
mother is able, without leaving her other occupations, to inspect them
daily and enquire tenderly into the progress of her family. I imagine,
without possessing any certain proof, that from time to time she
distributes additional provisions to the grubs, for the original loaf
appears to me a very frugal ration compared with that served by the
other Bees.

Certain hunting Hymenoptera, the Bembex-wasps, for instance, are
accustomed to furnish the provisions in instalments: so that the grub
may have fresh though dead game, they fill the platter each day. The
Halictus mother has not these domestic necessities, as her provisions
keep more easily; but still she might well distribute a second portion
of flour to the larvae, when their appetite attains its height. I can
see nothing else to explain the open doors of the cells during the
feeding-period.

At last the grubs, close-watched and fed to repletion, have achieved the
requisite degree of fatness; they are on the eve of being transformed
into pupae. Then and not till then the cells are closed: a big clay
stopper is built by the mother into the spreading mouth of the jug.
Henceforth the maternal cares are over. The rest will come of itself.

Hitherto we have witnessed only the peaceful details of the
housekeeping. Let us go back a little and we shall be witnesses of
rampant brigandage. In May, I visit my most populous village daily, at
about ten o'clock in the morning, when the victualling-operations are in
full swing. Seated on a low chair in the sun, with my back bent and my
arms upon my knees, I watch, without moving, until dinner-time. What
attracts me is a parasite, a trumpery Gnat, the bold despoiler of the
Halictus.

Has the jade a name? I trust so, without, however, caring to waste
my time in enquiries that can have no interest for the reader. Facts
clearly stated are preferable to the dry minutiae of nomenclature. Let
me content myself with giving a brief description of the culprit. She
is a Dipteron, or Fly, five millimetres long. (.195 inch.--Translator's
Note.) Eyes, dark-red; face, white. Corselet, pearl-grey, with five
rows of fine black dots, which are the roots of stiff bristles pointing
backwards. Greyish belly, pale below. Black legs.

She abounds in the colony under observation. Crouching in the sun,
near a burrow, she waits. As soon as the Halictus arrives from her
harvesting, her legs yellow with pollen, the Gnat darts forth and
pursues her, keeping behind her in all the turns of her oscillating
flight. At last, the Bee suddenly dives indoors. No less suddenly the
other settles on the mole-hill, quite close to the entrance. Motionless,
with her head turned towards the door of the house, she waits for the
Bee to finish her business. The latter reappears at last and, for a few
seconds, stands on the threshold, with her head and thorax outside the
hole. The Gnat, on her side, does not stir.

Often, they are face to face, separated by a space no wider than a
finger's breadth. Neither of them shows the least excitement. The
Halictus--judging, at least, by her tranquillity--takes no notice of
the parasite lying in wait for her; the parasite, on the other hand,
displays no fear of being punished for her audacity. She remains
imperturbable, she, the dwarf, in the presence of the colossus who could
crush her with one blow.

In vain I watch anxiously for some sign of apprehension on either side:
nothing in the Halictus points to a knowledge of the danger run by
her family; nor does the Gnat betray any dread of swift retribution.
Plunderer and plundered stare at each other for a moment; and that is
all.

If she liked, the amiable giantess could rip up with her claw the tiny
bandit who ruins her home; she could crunch her with her mandibles, run
her through with her stiletto. She does nothing of the sort, but leaves
the robber in peace, to sit quite close, motionless, with her red eyes
fixed on the threshold of the house. Why this fatuous clemency?

The Bee flies off. Forthwith, the Gnat walks in, with no more ceremony
than if she were entering her own place. She now chooses among the
victualled cells at her ease, for they are all open, as I have said;
she leisurely deposits her eggs. No one will disturb her until the Bee's
return. To flour one's legs with pollen, to distend one's crop with
syrup is a task that takes long a-doing; and the intruder, therefore,
has time and to spare wherein to commit her felony. Moreover, her
chronometer is well-regulated and gives the exact measure of the Bee's
length of absence. When the Halictus comes back from the fields, the
Gnat has decamped. In some favourable spot, not far from the burrow, she
awaits the opportunity for a fresh misdeed.

What would happen if a parasite were surprised at her work by the Bee?
Nothing serious. I see them, greatly daring, follow the Halictus right
into the cave and remain there for some time while the mixture of pollen
and honey is being prepared. Unable to make use of the paste so long as
the harvester is kneading it, they go back to the open air and wait
on the threshold for the Bee to come out. They return to the sunlight,
calmly, with unhurried steps: a clear proof that nothing untoward has
occurred in the depths where the Halictus works.

A tap on the Gnat's neck, if she become too enterprising in the
neighbourhood of the cake: that is all that the lady of the house seems
to allow herself, to drive away the intruder. There is no serious
affray between the robber and the robbed. This is apparent from the
self-possessed manner and undamaged condition of the dwarf who returns
from visiting the giantess engaged down in the burrow.

The Bee, when she comes home, whether laden with provisions or not,
hesitates, as I have said, for a while; in a series of rapid zigzags,
she moves backwards, forwards and from side to side, at a short distance
from the ground. This intricate flight at first suggests the idea
that she is trying to lead her persecutress astray by means of an
inextricable tangle of marches and countermarches. That would certainly
be a prudent move on the Bee's part; but so much wisdom appears to be
denied her.

It is not the enemy that is disturbing her, but rather the difficulty of
finding her own house amid the confusion of the mole-hills, encroaching
one upon the other, and all the alleys of the little township, which,
owing to landslips of fresh rubbish, alter in appearance from one day to
the next. Her hesitation is manifest, for she often blunders and alights
at the entrance to a burrow that is not hers. The mistake is at once
perceived from the slight indications of the doorway.

The search is resumed with the same see-sawing flights, mingled with
sudden excursions to a distance. At last, the burrow is recognized.
The Halictus dives into it with a rush; but, however prompt her
disappearance underground, the Gnat is there, perched on the threshold
with her eyes turned to the entrance, waiting for the Bee to come out,
so that she may visit the honey-jars in her turn.

When the owner of the house ascends, the other draws back a little, just
enough to leave a free passage and no more. Why should she put herself
out? the meeting is so peaceful that, short of further information, one
would not suspect that a destroyer and destroyed were face to face. Far
from being intimidated by the sudden arrival of the Halictus, the Gnat
pays hardly any attention; and, in the same way, the Halictus takes no
notice of her persecutress, unless the bandit pursue her and worry her
on the wing. Then, with a sudden bend, the Bee makes off.

Even so do Philanthus apivorus (The Bee-hunting Wasp. Cf. "Social Life
in the Insect World": chapter 13.--Translator's Note.) and the other
game-hunters behave when the Tachina is at their heels seeking the
chance to lay her egg on the morsel about to be stored away. Without
jostling the parasite which they find hanging around the burrow, they
go indoors quite peaceably; but, on the wing, perceiving her after them,
they dart off wildly. The Tachina, however, dares not go down to the
cells where the huntress stacks her provisions; she prudently waits at
the door for the Philanthus to arrive. The crime, the laying of the
egg, is committed at the very moment when the victim is about to vanish
underground.

The troubles of the parasite of the Halictus are of quite another
kind. The homing Bee has her honey in her crop and her pollen on her
leg-brushes: the first is inaccessible to the thief; the second is
powdery and would give no resting-place to the egg. Besides, there is
not enough of it yet: to collect the wherewithal for that round loaf of
hers, the Bee will have to make repeated journeys. When the necessary
amount is obtained, she will knead it with the tip of her mandibles
and shape it with her feet into a little ball. The Gnat's egg, were it
present among the materials, would certainly be in danger during this
manipulation.

The alien egg, therefore, must be laid on the finished bread; and, as
the preparation takes place underground, the parasite is needs obliged
to go down to the Halictus. With inconceivable daring, she does go
down, even when the Bee is there. Whether through cowardice or silly
indulgence, the dispossessed insect lets the other have its way.

The object of the Gnat, with her tenacious lying-in-wait and her
reckless burglaries, is not to feed herself at the harvester's expense:
she could get her living out of the flowers with much less trouble
than her thieving trade involves. The most, I think, that she can allow
herself to do in the Halictus' cellars is to take one morsel just to
ascertain the quality of the victuals. Her great, her sole business is
to settle her family. The stolen goods are not for herself, but for her
offspring.

Let us dig up the pollen-loaves. We shall find them most often crumbled
with no regard to economy, simply frittered away. We shall see two or
three maggots, with pointed mouths, moving in the yellow flour scattered
over the floor of the cell. These are the Gnat's progeny. With them
we sometimes find the lawful owner, the grub-worm of the Halictus, but
stunted and emaciated with fasting. His gluttonous companions, without
otherwise molesting him, deprive him of the best of everything. The
wretched starveling dwindles, shrivels up and soon disappears from view.
His corpse, a mere atom, blended with the remaining provisions, supplies
the maggots with one mouthful the more.

And what does the Halictus mother do in this disaster? She is free to
visit her grubs at any moment; she has but to put her head into the
passage of the house: she cannot fail to be apprised of their distress.
The squandered loaf, the swarming mass of vermin tell their own tale.
Why does she not take the intruders by the skin of the abdomen? To grind
them to powder with her mandibles, to fling them out of doors were
the business of a second. And the foolish creature never thinks of it,
leaves the ravagers in peace!

She does worse. When the time of the nymphosis comes, the Halictus
mother goes to the cells rifled by the parasite and closes them with an
earthen plug as carefully as she does the rest. This final barricade, an
excellent precaution when the cot is occupied by an Halictus in course
of metamorphosis, becomes the height of absurdity when the Gnat
has passed that way. Instinct does not hesitate in the face of this
ineptitude: it seals up emptiness. I say, emptiness, because the crafty
maggot hastens to decamp the instant that the victuals are consumed, as
though it foresaw an insuperable obstacle for the coming Fly: it quits
the cell before the Bee closes it.

To rascally guile the parasite adds prudence. All, until there is none
of them left, abandon the clay homes which would be their undoing once
the entrance was plugged up. The earthen niche, so grateful to the
tender skin, thanks to its polished coating, so free from humidity,
thanks to its waterproof glaze, ought, one would think, to make an
excellent waiting-place. The maggots will have none of it. Lest they
should find themselves walled in when they become frail Gnats, they go
away and disperse in the neighbourhood of the ascending shaft.

My digging operations, in fact, always reveal the pupae outside the
cells, never inside. I find them enshrined, one by one, in the body
of the clayey earth, in a narrow recess which the emigrant worm has
contrived to make for itself. Next spring, when the hour comes for
leaving, the adult insect has but to creep through the rubbish, which is
easy work.

Another and no less imperative reason compels this change of abode on
the parasite's part. In July, a second generation of the Halictus is
procreated. The Gnat, reduced on her side to a single brood, remains
in the pupa state and awaits the spring of the following year before
effecting her transformation. The honey-gather resumes her work in her
native village; she avails herself of the pits and cells constructed in
the spring, saving no little time thereby. The whole elaborate structure
has remained in good condition. It needs but a few repairs to make the
old house habitable.

Now what would happen if the Bee, so scrupulous in matters of
cleanliness, were to find a pupa in the cell which she is sweeping? She
would treat the cumbersome object as she would a piece of old plaster.
It would be no more to her than any other refuse, a bit of gravel,
which, seized with the mandibles, crushed perhaps, would be sent to join
the rubbish-heap outside. Once removed from the soil and exposed to the
inclemencies of the weather, the pupa would inevitably perish.

I admire this intelligent foresight of the maggot, which forgoes the
comfort of the moment for the security of the future. Two dangers
threaten it: to be immured in a casket whence the Fly can never issue;
or else to die out of doors, in the unkindly air, when the Bee sweeps
out the restored cells. To avoid this twofold peril, it decamps before
the door is closed, before the July Halictus sets her house in order.

Let us now see what comes of the parasite's intrusion. In the course
of June, when peace is established in the Halictus' home, I dig up
my largest village, comprising some fifty burrows in all. None of the
sorrows of this underworld shall escape me. There are four of us
engaged in sifting the excavated earth through our fingers. What one
has examined another takes up and examines; and then another and another
yet. The returns are heartrending. We do not succeed in finding one
single nymph of the Halictus. The whole of the populous city has
perished; and its place has been taken by the Gnat. There is a glut
of that individual's pupae. I collect them in order to trace their
evolution.

The year runs its course; and the little russet kegs, into which the
original maggots have hardened and contracted, remain stationary. They
are seeds endowed with latent life. The heats of July do not rouse them
from their torpor. In that month, the period of the second generation
of the Halictus, there is a sort of truce of God: the parasite rests and
the Bee works in peace. If hostilities were to be resumed straight
away, as murderous in summer as they were in spring, the progeny of the
Halictus, too cruelly smitten, might possibly disappear altogether. This
lull readjusts the balance.

In April, when the Zebra Halictus, in search of a good place for her
burrows, roams up and down the garden paths with her oscillating
flight, the parasite, on its side, hastens to hatch. Oh, the precise
and terrible agreement between those two calendars, the calendar of the
persecutor and the persecuted! At the very moment when the Bee comes
out, here is the Gnat: she is ready to begin her deadly starving-process
all over again.

Were this an isolated case, one's mind would not dwell upon it: an
Halictus more or less in the world makes little difference in the
general balance. But, alas, brigandage in all its forms is the rule in
the eternal conflict of living things! From the lowest to the highest,
every producer is exploited by the unproductive. Man himself, whose
exceptional rank ought to raise him above such baseness, excels in this
ravening lust. He says to himself that business means getting hold of
other people's cash, even as the Gnat says to herself that business
means getting hold of the Halictus' honey. And, to play the brigand
to better purpose, he invents war, the art of killing wholesale and of
doing with glory that which, when done on a smaller scale, leads to the
gallows.

Shall we never behold the realization of that sublime vision which is
sung on Sundays in the smallest village-church: Gloria in excelsis Deo,
et in terra pax hominibus bonae voluntatis! If war affected humanity
alone, perhaps the future would have peace in store for us, seeing that
generous minds are working for it with might and main; but the scourge
also rages among the lower animals, which in their obstinate way,
will never listen to reason. Once the evil is laid down as a general
condition, it perhaps becomes incurable. Life in the future, it is to be
feared, will be what it is to-day, a perpetual massacre.

Whereupon, by a desperate effort of the imagination, one pictures to
oneself a giant capable of juggling with the planets. He is irresistible
strength; he is also law and justice. He knows of our battles, our
butcheries, our farm-burnings, our town-burnings, our brutal triumphs;
he knows our explosives, our shells, our torpedo-boats, our ironclads
and all our cunning engines of destruction; he knows as well the
appalling extent of the appetites among all creatures, down to the
very lowest. Well, if that just and mighty one held the earth under his
thumb, would he hesitate whether he ought to crush it?

He would not hesitate...He would let things take their course. He would
say to himself:

'The old belief is right; the earth is a rotten apple, gnawed by the
vermin of evil. It is a first crude attempt, a step towards a kindlier
destiny. Let it be: order and justice are waiting at the end.'




CHAPTER 13. THE HALICTI: THE PORTRESS.

Leaving our village is no very serious matter when we are children. We
even look on it as a sort of holiday. We are going to see something new,
those magic pictures of our dreams. With age come regrets; and the close
of life is spent in stirring up old memories. Then the beloved village
reappears, in the biograph of the mind, embellished, transfigured by the
glow of those first impressions; and the mental image, superior to the
reality, stands out in amazingly clear relief. The past, the far-off
past, was only yesterday; we see it, we touch it.

For my part, after three-quarters of a century, I could walk with my
eyes closed straight to the flat stone where I first heard the soft
chiming note of the Midwife Toad; yes, I should find it to a certainty,
if time, which devastates all things, even the homes of Toads, has not
moved it or perhaps left it in ruins.

I see, on the margin of the brook, the exact position of the alder-trees
whose tangled roots, deep under the water, were a refuge for the
Crayfish. I should say:

'It is just at the foot of that tree that I had the unutterable bliss of
catching a beauty. She had horns so long...and enormous claws, full of
meat, for I got her just at the right time.'

I should go without faltering to the ash under whose shade my heart
beat so loudly one sunny spring morning. I had caught sight of a sort of
white, cottony ball among the branches. Peeping from the depths of
the wadding was an anxious little head with a red hood to it. O what
unparalleled luck! It was a Goldfinch, sitting on her eggs.

Compared with a find like this, lesser events do not count. Let us leave
them. In any case, they pale before the memory of the paternal garden,
a tiny hanging garden of some thirty paces by ten, situated right at
the top of the village. The only spot that overlooks it is a little
esplanade on which stands the old castle (The Chateau de Saint-Leons
standing just outside and above the village of Saint-Leons, where the
author was born in 1823. Cf. "The Life of the Fly": chapters 6 and
7.--Translator's Note.) with the four turrets that have now become
dovecotes. A steep path takes you up to this open space. From my house
on, it is more like a precipice than a slope. Gardens buttressed by
walls are staged in terraces on the sides of the funnel-shaped valley.
Ours is the highest; it is also the smallest.

There are no trees. Even a solitary apple-tree would crowd it. There
is a patch of cabbages, with a border of sorrel, a patch of turnips and
another of lettuces. That is all we have in the way of garden-stuff;
there is no room for more. Against the upper supporting-wall, facing due
south, is a vine-arbour which, at intervals, when the sun is generous,
provides half a basketful of white muscatel grapes. These are a luxury
of our own, greatly envied by the neighbours, for the vine is unknown
outside this corner, the warmest in the village.

A hedge of currant-bushes, the only safeguard against a terrible fall,
forms a parapet above the next terrace. When our parents' watchful eyes
are off us, we lie flat on our stomachs, my brother and I, and look into
the abyss at the foot of the wall bulging under the thrust of the land.
It is the garden of monsieur le notaire.

There are beds with box-borders in that garden; there are pear-trees
reputed to give pears, real pears, more or less good to eat when
they have ripened on the straw all through the late autumn. In our
imagination, it is a spot of perpetual delight, a paradise, but a
paradise seen the wrong way up: instead of contemplating it from below,
we gaze at it from above. How happy they must be with so much space and
all those pears!

We look at the hives, around which the hovering Bees make a sort of
russet smoke. They stand under the shelter of a great hazel. The tree
has sprung up all of itself in a fissure of the wall, almost on the
level of our currant-bushes. While it spreads its mighty branches over
the notary's hives, its roots, at least, are on our land. It belongs to
us. The trouble is to gather the nuts.

I creep along astride the strong branches projecting horizontally into
space. If I slip or if the support breaks, I shall come to grief in the
midst of the angry Bees. I do not slip and the support does not break.
With the bent switch which my brother hands me, I bring the finest
clusters within my reach. I soon fill my pockets. Moving backwards,
still straddling my branch, I recover terra firma. O wondrous days of
litheness and assurance, when, for a few filberts, on a perilous perch
we braved the abyss!

Enough. These reminiscences, so dear to my dreams, do not interest the
reader. Why stir up more of them? I am content to have brought this fact
into prominence: the first glimmers of light penetrating into the dark
chambers of the mind leave an indelible impression, which the years make
fresher instead of dimmer.

Obscured by everyday worries, the present is much less familiar to us,
in its petty details, than the past, with childhood's glow upon it. I
see plainly in my memory what my prentice eyes saw; and I should never
succeed in reproducing with the same accuracy what I saw last week. I
know my village thoroughly, though I quitted it so long ago; and I know
hardly anything of the towns to which the vicissitudes of life have
brought me. An exquisitely sweet link binds us to our native soil; we
are like the plant that has to be torn away from the spot where it put
out its first roots. Poor though it be, I should love to see my own
village again; I should like to leave my bones there.

Does the insect in its turn receive a lasting impression of its earliest
visions? Has it pleasant memories of its first surroundings? We will
not speak of the majority, a world of wandering gipsies who establish
themselves anywhere provided that certain conditions be fulfilled; but
the others, the settlers, living in groups: do they recall their native
village? Have they, like ourselves, a special affection for the place
which saw their birth?

Yes, indeed they have: they remember, they recognize the maternal abode,
they come back to it, they restore it, they colonize it anew. Among many
other instances, let us quote that of the Zebra Halictus. She will show
us a splendid example of love for one's birthplace translating itself
into deeds.

The Halictus' spring family acquire the adult form in a couple of months
or so; they leave the cells about the end of June. What goes on inside
these neophytes as they cross the threshold of the burrow for the
first time? Something, apparently, that may be compared with our own
impressions of childhood. An exact and indelible image is stamped on
their virgin memories. Despite the years, I still see the stone
whence came the resonant notes of the little Toads, the parapet of
currant-bushes, the notary's garden of Eden. These trifles make the best
part of my life. The Halictus sees in the same way the blade of grass
whereon she rested in her first flight, the bit of gravel which her claw
touched in her first climb to the top of the shaft. She knows her
native abode by heart just as I know my village. The locality has become
familiar to her in one glad, sunny morning.

She flies off, seeks refreshment on the flowers near at hand and visits
the fields where the coming harvests will be gathered. The distance does
not lead her astray, so faithful are her impressions of her first trip;
she finds the encampment of her tribe; among the burrows of the village,
so numerous and so closely resembling one another, she knows her own.
It is the house where she was born, the beloved house with its
unforgettable memories.

But, on returning home, the Halictus is not the only mistress of the
house. The dwelling dug by the solitary Bee in early spring remains,
when summer comes, the joint inheritance of the members of the family.
There are ten cells, or thereabouts, underground. Now from these cells
there have issued none but females. This is the rule among the three
species of Halicti that concern us now and probably also among many
others, if not all. They have two generations in each year. The spring
one consists of females only; the summer one comprises both males
and females, in almost equal numbers. We shall return to this curious
subject in our next chapter.

The household, therefore, if not reduced by accidents, above all if not
starved by the usurping Gnat, would consist of half-a-score of sisters,
none but sisters, all equally industrious and all capable of procreating
without a nuptial partner. On the other hand, the maternal dwelling is
no hovel; far from it: the entrance-gallery, the principal room of the
house, will serve quite well, after a few odds and ends of refuse have
been swept away. This will be so much gained in time, ever precious
to the Bee. The cells at the bottom, the clay cabins, are also nearly
intact. To make use of them, it will be enough for the Halictus to
polish up the stucco with her tongue.

Well, which of the survivors, all equally entitled to the succession,
will inherit the house? There are six of them, seven, or more, according
to the chances of mortality. To whose share will the maternal dwelling
fall?

There is no quarrel between the interested parties. The mansion is
recognized as common property without dispute. The sisters come and go
peacefully through the same door, attend to their business, pass and
let the others pass. Down at the bottom of the pit, each has her little
demesne, her group of cells dug at the cost of fresh toil, when the old
ones, now insufficient in number, are occupied. In these recesses,
which are private estates, each mother works by herself, jealous of her
property and of her privacy. Every elsewhere, traffic is free to all.

The exits and entrances in the working fortress provide a spectacle
of the highest interest. A harvester arrives from the fields, the
feather-brushes of her legs powdered with pollen. If the door be open,
the Bee at once dives underground. To tarry on the threshold would mean
waste of time; and the business is urgent. Sometimes, several appear
upon the scene at almost the same moment. The passage is too narrow for
two, especially when they have to avoid any untimely contact that would
make the floury burden fall to the floor. The nearest to the opening
enters quickly. The others, drawn up on the threshold in order of their
arrival, respectful of one another's rights, await their turn. As soon
as the first disappears, the second follows after her and is herself
swiftly followed by the third and then the others, one by one.

Sometimes, again, there is a meeting between a Bee about to come out and
a Bee about to go in. Then the latter draws back a little and makes way
for the former. The politeness is reciprocal. I see some who, when on
the point of emerging from the pit, go down again and leave the passage
free for the one who has just arrived. Thanks to this mutual spirit of
accommodation, the business of the house proceeds without impediment.

Let us keep our eyes open. There is something better than the
well-preserved order of the entrances. When an Halictus appears,
returning from her round of the flowers, we see a sort of trap-door,
which closed the house, suddenly fall and give a free passage. As soon
as the new arrival has entered, the trap rises back into its place,
almost level with the ground, and closes the entrance anew. The same
thing happens when the insects go out. At a request from within, the
trap descends, the door opens and the Bee flies away. The outlet is
closed forthwith.

What can this valve be which, descending or ascending in the cylinder
of the pit, after the fashion of a piston, opens and closes the house
at each departure and at each arrival? It is an Halictus, who has become
the portress of the establishment. With her large head, she makes an
impassable barrier at the top of the entrance-hall. If any one belonging
to the house wants to go in or out, she 'pulls the cord,' that is to
say, she withdraws to a spot where the gallery becomes wider and leaves
room for two. The other passes. She then at once returns to the
orifice and blocks it with the top of her head. Motionless, ever on the
look-out, she does not leave her post save to drive away importunate
visitors.

Let us profit by her brief appearances outside to take a look at her. We
recognize in her an Halictus similar to the others, which are now busy
harvesting; but the top of her head is bald and her dress is dingy
and thread-bare. All the nap is gone; and one can hardly make out
the handsome stripes of red and brown which she used to have. These
tattered, work-worn garments make things clear to us.

This Bee who mounts guard and performs the office of a portress at the
entrance to the burrow is older than the others. She is the foundress of
the establishment, the mother of the actual workers, the grandmother of
the present grubs. In the springtime of her life, three months ago, she
wore herself out in solitary labours. Now that her ovaries are dried
up, she takes a well-earned rest. No, rest is hardly the word. She still
works, she assists the household to the best of her power. Incapable of
being a mother for a second time, she becomes a portress, opens the door
to the members of her family and makes strangers keep their distance.

The suspicious Kid (In La Fontaine's fable, "Le Loup, la Chevre et le
Chevreau."--Translator's Note.), looking through the chink, said to the
Wolf:

'Show me a white foot, or I shan't open the door.'

No less suspicious, the grandmother says to each comer:

'Show me the yellow foot of an Halictus, or you won't be let in.'

None is admitted to the dwelling unless she be recognized as a member of
the family.

See for yourselves. Near the burrow passes an Ant, an unscrupulous
adventuress, who would not be sorry to know the meaning of the honeyed
fragrance that rises from the bottom of the cellar.

"Be off, or you'll catch it!' says the portress, wagging her neck.

As a rule the threat suffices. The Ant decamps. Should she insist,
the watcher leaves her sentry-box, flings herself upon the saucy jade,
buffets her and drives her away. The moment the punishment has been
administered, she returns to her post.

Next comes the turn of a Leaf-cutter (Megachile albocincta, PEREZ),
which, unskilled in the art of burrowing, utilizes, after the manner of
her kin, the old galleries dug by others. Those of the Zebra Halictus
suit her very well, when the terrible Gnat has left them vacant for
lack of heirs. Seeking for a home wherein to stack her robinia-leaf
honey-pots, she often makes a flying inspection of my colonies of
Halicti. A burrow seems to take her fancy; but, before she sets foot on
earth, her buzzing is noticed by the sentry, who suddenly darts out
and makes a few gestures on the threshold of her door. That is all. The
Leaf-cutter has understood. She moves on.

Sometimes, the Megachile has time to alight and insert her head into
the mouth of the pit. In a moment, the portress is there, comes a
little higher and bars the way. Follows a not very serious contest.
The stranger quickly recognizes the rights of the first occupant and,
without insisting, goes to seek an abode elsewhere.

An accomplished marauder (Caelioxys caudata, SPIN.), a parasite of the
Megachile, receives a sound drubbing under my eyes. She thought, the
feather-brain, that she was entering the Leaf-Cutter's establishment!
She soon finds out her mistake; she meets the door-keeping Halictus, who
administers a sharp correction. She makes off at full speed. And so with
the others which, through inadvertence or ambition, seek to enter the
burrow.

The same intolerance exists among the different grandmothers. About the
middle of July, when the animation of the colony is at its height, two
sets of Halicti are easily distinguishable: the young mothers and the
old. The former, much more numerous, brisk of movement and smartly
arrayed, come and go unceasingly from the burrows to the fields and from
the fields to the burrows. The latter, faded and dispirited, wander idly
from hole to hole. They look as though they had lost their way and were
incapable of finding their homes. Who are these vagabonds? I see in them
afflicted ones bereft of a family through the act of the odious Gnat.
Many burrows have been altogether exterminated. At the awakening of
summer, the mother found herself alone. She left her empty house and
went off in search of a dwelling where there were cradles to defend, a
guard to mount. But those fortunate nests already have their overseer,
the foundress, who, jealous of her rights, gives her unemployed
neighbour a cold reception. One sentry is enough; two would merely block
the narrow guard-room.

I am privileged at times to witness a fight between two grandmothers.
When the tramp in quest of employment appears outside the door, the
lawful occupant does not move from her post, does not withdraw into the
passage, as she would before an Halictus returning from the fields. Far
from making way, she threatens the intruder with her feet and mandibles.
The other retaliates and tries to force her way in notwithstanding.
Blows are exchanged. The fray ends by the defeat of the stranger, who
goes off to pick a quarrel elsewhere.

These little scenes afford us a glimpse of certain details of the
highest interest in the habits of the Zebra Halictus. The mother who
builds her nest in the spring no longer leaves her home, once her works
are finished. Shut up at the bottom of the burrow, busied with the
thousand cares of housekeeping, or else drowsing, she waits for her
daughters to come out. When, in the summer heats, the life of the
village recommences, having nought to do outside as a harvester, she
stands sentry at the entrance to the hall, so as to let none in save the
workers of the home, her own daughters. She wards off evilly-disposed
visitors. None can enter without the door-keeper's consent.

There is nothing to tell us that the watcher ever deserts her post. Not
once do I see her leave her house to go and seek some refreshment from
the flowers. Her age and her sedentary occupation, which involves no
great fatigue, perhaps relieve her of the need of nourishment. Perhaps,
also, the young ones returning from their plundering may from time to
time disgorge a drop of the contents of their crops for her benefit. Fed
or unfed, the old one no longer goes out.

But what she does need is the joys of an active family. Many are
deprived of these. The Gnat's burglary has destroyed the busy household.
The sorely-tried Bees abandon the deserted burrow. It is they who,
ragged and careworn, wander through the village. When they move, their
flight is only a short one; more often they remain motionless. It is
they who, soured in their tempers, attack their fellows and seek to
dislodge them. They grow rarer and more languid from day to day; then
they disappear for good. What has become of them? The little Grey Lizard
had his eye on them: they are easily snapped up.

Those settled in their own demesne, those who guard the honey-factory
wherein their daughters, the heiresses of the maternal establishment,
are at work, display wonderful vigilance. The more I see of them, the
more I admire them. In the cool hours of the early morning, when the
pollen-flour is not sufficiently ripened by the sun and while the
harvesters are still indoors, I see them at their posts, at the top of
the gallery. Here, motionless, their heads flush with the earth, they
bar the door to all invaders. If I look at them closely, they retreat a
little and, in the shadow, await the indiscreet observer's departure.

I return when the harvesting is in full swing, between eight o'clock
and twelve. There is now, as the Halicti go in or out, a succession
of prompt withdrawals to open the door and of ascents to close it. The
portress is in the full exercise of her functions.

In the afternoon, the heat is too great and the workers do not go to the
fields. Retiring to the bottom of the house, they varnish the new cells,
they make the round loaf that is to receive the egg. The grandmother is
still upstairs, stopping the door with her bald head. For her, there
is no siesta during the stifling hours: the safety of the household
requires her to forgo it.

I come back again at nightfall, or even later. By the light of a
lantern, I again behold the overseer, as zealous and assiduous as in the
day-time. The others are resting, but not she, for fear, apparently, of
nocturnal dangers known to herself alone. Does she nevertheless end
by descending to the quiet of the floor below? It seems probable, so
essential must rest be, after the fatigue of such a vigil!

It is evident that, guarded in this manner, the burrow is exempt from
calamities similar to those which, too often, depopulate it in May. Let
the Gnat come now, if she dare, to steal the Halictus' loaves! Let her
lie in wait as long as she will! Neither her audacity nor her slyness
will make her escape the lynx eyes of the sentinel, who will put her to
flight with a threatening gesture or, if she persist, crush her with
her nippers. She will not come; and we know the reason: until spring
returns, she is underground in the pupa state.

But, in her absence, there is no lack, among the Fly rabble, of other
batteners on the toil of their fellow insects. Whatever the job,
whatever the plunder, you will find parasites there. And yet, for all
my daily visits, I never catch one of these in the neighbourhood of the
summer burrows. How cleverly the rascals ply their trade! How well aware
are they of the guard who keeps watch at the Halictus' door! There is
no foul deed possible nowadays; and the result is that no Fly puts in an
appearance and the tribulations of last spring are not repeated.

The grandmother who, dispensed by age from maternal bothers, mounts
guard at the entrance of the home and watches over the safety of the
family, tells us that in the genesis of the instincts sudden births
occur; she shows us the existence of a spontaneous aptitude which
nothing, either in her own past conduct or in the actions of her
daughters, could have led us to suspect. Timorous in her prime, in the
month of May, when she lived alone in the burrow of her making, she
has become gifted, in her decline, with a superb contempt of danger and
dares in her impotence what she never dared do in her strength.

Formerly, when her tyrant, the Gnat, entered the house in her presence,
or, more often, stood face to face with her at the entrance, the silly
Bee did not stir, did not even threaten the red-eyed bandit, the dwarf
whose doom she could so easily have sealed. Was it terror on her part?
No, for she attended to her duties with her usual punctiliousness; no,
for the strong do not allow themselves to be thus paralysed by the weak.
It was ignorance of the danger, it was sheer fecklessness.

And behold, to-day, the ignoramus of three months ago knows the peril,
knows it well, without serving any apprenticeship. Every stranger who
appears is kept at a distance, without distinction of size or race.
If the threatening gesture be not enough, the keeper sallies forth and
flings herself upon the persistent one. Cowardice has developed into
courage.

How has this change been brought about? I should like to picture the
Halictus gaining wisdom from the misfortunes of the spring and capable
thenceforth of looking out for danger; I would gladly credit her with
having learnt in the stern school of experience the advantages of a
patrol. I must give up the idea. If, by dint of gradual little acts of
progress, the Bee has achieved the glorious invention of a janitress,
how comes it that the fear of thieves is intermittent? It is true that,
being by herself in May, she cannot stand permanently at her door:
the business of the house takes precedence of everything else. But she
ought, at any rate as soon as her offspring are victimized, to know
the parasite and give chase when, at every moment, she finds her almost
under her feet and even in her house. Yet she pays no attention to her.

The bitter experience of her ancestors, therefore, has bequeathed
nothing to her of a nature to alter her placid character; nor have her
own tribulations aught to do with the sudden awakening of her vigilance
in July. Like ourselves, animals have their joys and their sorrows.
They eagerly make the most of the former; they fret but little about the
latter, which, when all is said, is the best way of achieving a purely
animal enjoyment of life. To mitigate these troubles and protect the
progeny there is the inspiration of instinct, which is able without the
counsels of experience to give the Halicti a portress.

When the victualling is finished, when the Halicti no longer sally forth
on harvesting intent nor return all befloured with their spoils, the old
Bee is still at her post, vigilant as ever. The final preparations for
the brood are made below; the cells are closed. The door will be kept
until everything is finished. Then grandmother and mothers leave the
house. Exhausted by the performance of their duty, they go, somewhere or
other, to die.

In September appears the second generation, comprising both males and
females. I find both sexes wassailing on the flowers, especially the
Compositae, the centauries and thistles. They are not harvesting now:
they are refreshing themselves, holding high holiday, teasing one
another. It is the wedding-time. Yet another fortnight and the males
will disappear, henceforth useless. The part of the idlers is played.
Only the industrious ones remain, the impregnated females, who go
through the winter and set to work in April.

I do not know their exact haunt during the inclement season. I expected
them to return to their native burrow, an excellent dwelling for the
winter, one would think. Excavations made in January showed me my
mistake. The old homes are empty, are falling to pieces owing to the
prolonged effect of the rains. The Zebra Halictus has something better
than these muddy hovels: she has snug corners in the stone-heaps,
hiding-places in the sunny walls and many other convenient habitations.
And so the natives of a village become scattered far and wide.

In April, the scattered ones reassemble from all directions. On the
well-flattened garden-paths a choice is made of the site for their
common labours. Operations soon begin. Close to the first who bores
her shaft there is soon a second one busy with hers; a third arrives,
followed by another and others yet, until the little mounds often touch
one another, while at times they number as many as fifty on a surface of
less than a square yard.

One would be inclined, at first sight, to say that these groups are
accounted for by the insect's recollection of its birthplace, by the
fact that the villagers, after dispersing during the winter, return to
their hamlet. But it is not thus that things happen: the Halictus scorns
to-day the place that once suited her. I never see her occupy the same
patch of ground for two years in succession. Each spring she needs new
quarters. And there are plenty of them.

Can this mustering of the Halicti be due to a wish to resume the old
intercourse with their friends and relations? Do the natives of the same
burrow, of the same hamlet, recognize one another? Are they inclined to
do their work among themselves rather than in the company of strangers?
There is nothing to prove it, nor is there anything to disprove it.
Either for this reason or for others, the Halictus likes to keep with
her neighbours.

This propensity is pretty frequent among peace-lovers, who, needing
little nourishment, have no cause to fear competition. The others, the
big eaters, take possession of estates, of hunting-grounds from which
their fellows are excluded. Ask a Wolf his opinion of a brother Wolf
poaching on his preserves. Man himself, the chief of consumers, makes
for himself frontiers armed with artillery; he sets up posts at the foot
of which one says to the other:

'Here's my side, there's yours. That's enough: now we'll pepper each
other.'

And the rattle of the latest explosives ends the colloquy.

Happy are the peace-lovers. What do they gain by their mustering? With
them it is not a defensive system, a concerted effort to ward off the
common foe. The Halictus does not care about her neighbour's affairs.
She does not visit another's burrow; she does not allow others to
visit hers. She has her tribulations, which she endures alone; she is
indifferent to the tribulations of her kind. She stands aloof from the
strife of her fellows. Let each mind her own business and leave things
at that.

But company has its attractions. He lives twice who watches the life of
others. Individual activity gains by the sight of the general activity;
the animation of each one derives fresh warmth from the fire of the
universal animation. To see one's neighbours at work stimulates one's
rivalry. And work is the great delight, the real satisfaction that gives
some value to life. The Halictus knows this well and assembles in her
numbers that she may work all the better.

Sometimes she assembles in such multitudes and over such extents of
ground as to suggest our own colossal swarms. Babylon and Memphis, Rome
and Carthage, London and Paris, those frantic hives, occur to our mind
if we can manage to forget comparative dimensions and see a Cyclopean
pile in a pinch of earth.

It was in February. The almond-tree was in blossom. A sudden rush of
sap had given the tree new life; its boughs, all black and desolate,
seemingly dead, were becoming a glorious dome of snowy satin. I have
always loved this magic of the awakening spring, this smile of the first
flowers against the gloomy bareness of the bark.

And so I was walking across the fields, gazing at the almond-trees'
carnival. Others were before me. An Osmia in a black velvet bodice and
a red woollen skirt, the Horned Osmia, was visiting the flowers, dipping
into each pink eye in search of a honeyed tear. A very small and very
modestly-dressed Halictus, much busier and in far greater numbers, was
flitting silently from blossom to blossom. Official science calls her
Halictus malachurus, K. The pretty little Bee's godfather strikes me as
ill-inspired. What has malachurus, calling attention to the softness
of the rump, to do in this connection? The name of Early Halictus would
better describe the almond-tree's little visitor.

None of the melliferous clan, in my neighbourhood at least, is stirring
as early as she is. She digs her burrows in February, an inclement
month, subject to sudden returns of frost. When none as yet, even among
her near kinswomen, dares to sally forth from winter-quarters, she
pluckily goes to work, shine the sun ever so little. Like the Zebra
Halictus, she has two generations a year, one in spring and one in
summer; like her, too, she settles by preference in the hard ruts of the
country roads.

Her mole-hills, those humble mounds any two of which would go
easily into a Hen's egg, rise innumerous in my path, the path by the
almond-trees which is the happy hunting-ground of my curiosity to-day.
This path is a ribbon of road three paces wide, worn into ruts by the
Mule's hoofs and the wheels of the farm-carts. A coppice of holm-oaks
shelters it from the north wind. In this Eden with its well-caked soil,
its warmth and quiet, the little Halictus has multiplied her mole-hills
to such a degree that I cannot take a step without crushing some of
them. The accident is not serious: the miner, safe underground, will
be able to scramble up the crumbling sides of the mine and repair the
threshold of the trampled home.

I make a point of measuring the density of the population. I count
from forty to sixty mole-hills on a surface of one square yard. The
encampment is three paces wide and stretches over nearly three-quarters
of a mile. How many Halicti are there in this Babylon? I do not venture
to make the calculation.

Speaking of the Zebra Halictus, I used the words hamlet, village,
township; and the expressions were appropriate. Here the term city
hardly meets the case. And what reason can we allege for these
innumerable clusters? I can see but one: the charm of living together,
which is the origin of society. Like mingles with like, without the
rendering of any mutual service; and this is enough to summon the Early
Halictus to the same way-side, even as the Herring and the Sardine
assemble in the same waters.




CHAPTER 14. THE HALICTI: PARTHENOGENESIS.

The Halictus opens up another question, connected with one of life's
obscurest problems. Let us go back five-and-twenty years. I am living at
Orange. My house stands alone among the fields. On the other side of
the wall enclosing our yard, which faces due south, is a narrow path
overgrown with couch-grass. The sun beats full upon it; and the glare
reflected from the whitewash of the wall turns it into a little tropical
corner, shut off from the rude gusts of the north-west wind.

Here the Cats come to take their afternoon nap, with their eyes
half-closed; here the children come, with Bull, the House-dog; here
also come the haymakers, at the hottest time of the day, to sit and take
their meal and whet their scythes in the shade of the plane-tree; here
the women pass up and down with their rakes, after the hay-harvest, to
glean what they can on the niggardly carpet of the shorn meadow. It is
therefore a very much frequented footpath, were it only because of the
coming and going of our household: a thoroughfare ill-suited, one would
think, to the peaceful operations of a Bee; and nevertheless it is such
a very warm and sheltered spot and the soil is so favourable that every
year I see the Cylindrical Halictus (H. cylindricus, FAB.) hand down
the site from one generation to the next. It is true that the very
matutinal, even partly nocturnal character of the work makes the insect
suffer less inconvenience from the traffic.

The burrows cover an extent of some ten square yards, and their mounds,
which often come near enough to touch, average a distance of four inches
at the most from one another. Their number is therefore something like
a thousand. The ground just here is very rough, consisting of stones
and dust mixed with a little mould and held together by the closely
interwoven roots of the couch-grass. But, owing to its nature, it is
thoroughly well drained, a condition always in request among Bees and
Wasps that have underground cells.

Let us forget for a moment what the Zebra Halictus and the Early
Halictus have taught us. At the risk of repeating myself a little,
I will relate what I observed during my first investigations. The
Cylindrical Halictus works in May. Except among the social species, such
as Common Wasps, Bumble-bees, Ants and Hive-bees, it is the rule for
each insect that victuals its nests either with honey or game to work by
itself at constructing the home of its grubs. Among insects of the same
species there is often neighbourship; but their labours are individual
and not the result of co-operation. For instance, the Cricket-hunters,
the Yellow-winged Sphex, settle in gangs at the foot of a sandstone
cliff, but each digs her own burrow and would not suffer a neighbour to
come and help in piercing the home.

In the case of the Anthophorae, an innumerable swarm takes possession
of a sun-scorched crag, each Bee digging her own gallery and jealously
excluding any of her fellows who might venture to come to the entrance
of her hole. The Three-pronged Osmia, when boring the bramble-stalk
tunnel in which her cells are to be stacked, gives a warm reception to
any Osmia that dares set foot upon her property.

Let one of the Odyneri who make their homes in a road-side bank mistake
the door and enter her neighbour's house: she would have a bad time of
it! Let a Megachile, returning with her leafy disk in her legs, go
into the wrong basement: she would be very soon dislodged! So with the
others: each has her own home, which none of the others has the right
to enter. This is the rule, even among Bees and Wasps established in a
populous colony on a common site. Close neighbourhood implies no sort of
intimate relationship.

Great therefore is my surprise as I watch the Cylindrical Halictus'
operations. She forms no society, in the entomological sense of the
word: there is no common family; and the general interest does not
engross the attention of the individual. Each mother occupies herself
only with her own eggs, builds cells and gathers honey only for her own
larvae, without concerning herself in any way with the upbringing of the
others' grubs. All that they have in common is the entrance-door and
the goods-passage, which ramifies in the ground and leads to different
groups of cells, each the property of one mother. Even so, in the blocks
of flats in our large towns, one door, one hall and one staircase lead
to different floors or different portions of a floor where each family
retains its isolation and its independence.

This common right of way is extremely easy to perceive at the time for
victualling the nests. Let us direct our attention for a while to the
same entrance-aperture, opening at the top of a little mound of earth
freshly thrown up, like that accumulated by the Ants during their works.
Sooner or later we shall see the Halicti arrive with their load of
pollen, gathered on the Cichoriaceae of the neighbourhood.

Usually, they come up one by one; but it is not rare to see three, four
or even more appearing at the same time at the mouth of one burrow.
They perch on the top of the mound and, without hurrying in front of one
another, with no sign of jealousy, they dive down the passage, each
in her turn. We need but watch their peaceful waiting, their tranquil
dives, to recognize that this indeed is a common passage to which each
has as much right as another.

When the soil is exploited for the first time and the shaft sunk slowly
from the outside to the inside, do several Cylindrical Halicti, one
relieving the other, take part in the work by which they will afterwards
profit equally? I do not believe it for a moment. As the Zebra Halictus
and the Early Halictus told me later, each miner goes to work alone and
makes herself a gallery which will be her exclusive property. The common
use of the passage comes presently, when the site, tested by experience,
is handed down from one generation to another.

A first group of cells is established, we will suppose, at the bottom of
a pit dug in virgin soil. The whole thing, cells and pit, is the work of
one insect. When the moment comes to leave the underground dwelling, the
Bees emerging from this nest will find before them an open road, or one
at most obstructed by crumbly matter, which offers less resistance than
the neighbouring soil, as yet untouched. The exit-way will therefore be
the primitive way, contrived by the mother during the construction of
the nest. All enter upon it without any hesitation, for the cells open
straight on it. All, coming and going from the cells to the bottom
of the shaft and from the shaft to the cells, will take part in the
clearing, under the stimulus of the approaching deliverance.

It is quite unnecessary here to presume among these underground
prisoners a concerted effort to liberate themselves more easily by
working in common: each is thinking only of herself and invariably
returns, after resting, to toil at the inevitable path, the path of
least resistance, in short the passage once dug by the mother and now
more or less blocked up.

Among the Cylindrical Halicti, any one who wishes emerges from her
cell at her own hour, without waiting for the emergence of the others,
because the cells, grouped in small stacks, have each their special
outlet opening into the common gallery. The result of this arrangement
is that all the inhabitants of one burrow are able to assist, each doing
her share, in the clearing of the exit-shaft. When she feels fatigued,
the worker retires to her undamaged cell and another succeeds her,
impatient to get out rather than to help the first. At last the way is
clear and the Halicti emerge. They disperse over the flowers around as
long as the sun is hot; when the air cools, they go back to the burrows
to spend the night there.

A few days pass and already the cares of egg-laying are at hand. The
galleries have never been abandoned. The Bees have come to take refuge
there on rainy or very windy days; most, if not all, have returned every
evening at sunset, each doubtless making for her own cell, which is
still intact and which is carefully impressed upon her memory. In a
word, the Cylindrical Halictus does not lead a wandering life; she has a
fixed residence.

A necessary consequence results from these settled habits: for the
purpose of her laying, the Bee will adopt the identical burrow in which
she was born. The entrance-gallery is ready therefore. Should it need to
be carried deeper, to be pushed in new directions, the builder has but
to extend it at will. The old cells even can serve again, if slightly
restored.

Thus resuming possession of the native burrow in view of her offspring,
the Bee, notwithstanding her instincts as a solitary worker, achieves
an attempt at social life, because there is one entrance-door and
one passage for the use of all the mothers returning to the original
domicile. There is thus a semblance of collaboration without any real
co-operation for the common weal. Everything is reduced to a family
inheritance shared equally among the heirs.

The number of these coheirs must soon be limited, for a too tumultuous
traffic in the corridor would delay the work. Then fresh passages are
opened inwards, often communicating with depths already excavated,
so that the ground at last is perforated in every direction with an
inextricable maze of winding tunnels.

The digging of the cells and the piercing of new galleries take place
especially at night. A cone of fresh earth on top of the burrow bears
evidence every morning to the overnight activity. It also shows by its
volume that several navvies have taken part in the work, for it would be
impossible for a single Halictus to extract from the ground, convey to
the surface and heap up so large a stack of rubbish in so short a time.

At sunrise, when the fields around are still wet with dew, the
Cylindrical Halictus leaves her underground passages and starts on her
foraging. This is done without animation, perhaps because of the morning
coolness. There is no joyous excitement, no humming above the burrows.
The Bees come back again, flying low, silently and heavily, their
hind-legs yellow with pollen; they alight on the earth-cone and at once
dive down the vertical chimney. Others come up the pipe and go off to
their harvesting.

This journeying to and fro for provisions continues until eight or nine
in the morning. Then the heat begins to grow intense and is reflected
by the wall; then also the path is once more frequented. People pass at
every moment, coming out of the house or elsewhence. The soil is so much
trodden under foot that the little mounds of refuse surrounding each
burrow soon disappear and the site loses every sign of underground
habitation.

All day long, the Halicti remain indoors. Withdrawing to the bottom of
the galleries, they occupy themselves probably in making and polishing
the cells. Next morning, new cones of rubbish appear, the result of the
night's work, and the pollen-harvest is resumed for a few hours; then
everything ceases again. And so the work goes on, suspended by day,
renewed at night and in the morning hours, until completely finished.

The passages of the Cylindrical Halictus descend to a depth of some
eight inches and branch into secondary corridors, each giving access
to a set of cells. These number six or eight to each set and are ranged
side by side, parallel with their main axis, which is almost horizontal.
They are oval at the base and contracted at the neck. Their length is
nearly twenty millimetres (.78 inch.--Translator's Note.) and their
greatest width eight. (.312 inch.--Translator's Note.) They do not
consist simply of a cavity in the ground; on the contrary, they have
their own walls, so that the group can be taken out in one piece, with
a little precaution, and removed neatly from the earth in which it is
contained.

The walls are formed of fairly delicate materials, which must have
been chosen in the coarse surrounding mass and kneaded with saliva.
The inside is carefully polished and upholstered with a thin waterproof
film. We will cut short these details concerning the cells, which the
Zebra Halictus has already shown us in greater perfection, leave the
home to itself and come to the most striking feature in the life-history
of the Halicti.

The Cylindrical Halictus is at work in the first days of May. It is
a rule among the Hymenoptera for the males never to take part in
the fatiguing work of nest-building. To construct cells and to amass
victuals are occupations entirely foreign to their nature. This rule
seems to have no exceptions; and the Halicti conform to it like the
rest. It is therefore only to be expected that we should see no males
shooting the underground rubbish outside the galleries. That is not
their business.

But what does astonish us, when our attention is directed to it, is the
total absence of any males in the vicinity of the burrows. Although it
is the rule that the males should be idle, it is also the rule for these
idlers to keep near the galleries in course of construction, coming and
going from door to door and hovering above the work-yards to seize the
moment at which the unfecundated females will at last yield to their
importunities.

Now here, despite the enormous population, despite my careful and
incessant watch, it is impossible for me to distinguish a single male.
And yet the distinction between the sexes is of the simplest. It is
not necessary to take hold of the male. He can be recognized even at a
distance by his slenderer frame, by his long, narrow abdomen, by his red
sash. They might easily suggest two different species. The female is
a pale russet-brown; the male is black, with a few red segments to his
abdomen. Well, during the May building-operations, there is not a Bee in
sight clad in black, with a slender, red-belted abdomen; in short, not a
male.

Though the males do not come to visit the environs of the burrows, they
might be elsewhere, particularly on the flowers where the females go
plundering. I did not fail to explore the fields, insect-net in hand.
My search was invariably fruitless. On the other hand, those males,
now nowhere to be found, are plentiful later, in September, along the
borders of the paths, on the close-set flowers of the eringo.

This singular colony, reduced exclusively to mothers, made me suspect
the existence of several generations a year, whereof one at least must
possess the other sex. I continued therefore, when the building-who
was over, to keep a daily watch on the establishment of the Cylindrical
Halictus, in order to seize the favourable moment that would verify my
suspicions. For six weeks, solitude reigned above the burrows: not a
single Halictus appeared; and the path, trodden by the wayfarers, lost
its little heaps of rubbish, the only signs of the excavations. There
was nothing outside to show that the warmth down below was hatching
populous swarms.

July comes and already a few little mounds of fresh earth betoken work
going on underground in preparation for an exodus in the near future.
As the males, among the Hymenoptera, are generally further advanced than
the females and quit their natal cells earlier, it was important that I
should witness the first exits made, so as to dispel the least shadow
of a doubt. A violent exhumation would have a great advantage over the
natural exit: it would place the population of the burrows immediately
under my eyes, before the departure of either sex. In this way, nothing
could escape from me and I was dispensed from a watch which, for all its
attentiveness, was not to be relied upon absolutely. I therefore resolve
upon a reconnaissance with the spade.

I dig down to the full depth of the galleries and remove large lumps of
earth which I take in my hands and break very carefully so as to examine
all the parts that may contain cells. Halicti in the perfect state
predominate, most of them still lodged in their unbroken chambers.
Though they are not quite so numerous, there are also plenty of pupae.
I collect them of every shade of colour, from dead-white, the sign of
a recent transformation, to smoky-brown, the mark of an approaching
metamorphosis. Larvae, in small quantities, complete the harvest. They
are in the state of torpor that precedes the appearance of the pupa.

I prepare boxes with a bed of fresh, sifted earth to receive the larvae
and the pupae, which I lodge each in a sort of half-cell formed by the
imprint of my finger. I will await the transformation to decide to which
sex they belong. As for the perfect insects, they are inspected, counted
and at once released.

In the very unlikely supposition that the distribution of the sexes
might vary in different parts of the colony, I make a second excavation,
at a few yards' distance from the other. It supplies me with another
collection both of perfect insects and of pupae and larvae.

When the metamorphosis of the laggards is completed, which does not take
many days, I proceed to take a general census. It gives me two hundred
and fifty Halicti. Well, in this number of Bees, collected in the burrow
before any have emerged, I perceive none, absolutely none but females;
or, to be mathematically accurate, I find just one male, one alone;
and he is so small and feeble that he dies without quite succeeding in
divesting himself of his nymphal bands. This solitary male is certainly
accidental. A female population of two hundred and forty-nine Halicti
implies other males than this abortion, or rather implies none at all. I
therefore eliminate him as an accident of no value and conclude that, in
the Cylindrical Halictus, the July generation consists of females only.

The building-operations start again in the second week of July. The
galleries are restored and lengthened; new cells are fashioned and the
old ones repaired. Follow the provisioning, the laying of the eggs, the
closing of the cells; and, before July is over, there is solitude again.
Let me also say that, during the building-period, not a male appears in
sight, a fact which adds further proof to that already supplied by my
excavations.

With the high temperature of this time of the year, the development of
the larvae makes rapid progress: a month is sufficient for the various
stages of the metamorphosis. On the 24th of August there are once more
signs of life above the burrows of the Cylindrical Halictus, but under
very different conditions. For the first time, both sexes are present.
Males, so easily recognized by their black livery and their slim abdomen
adorned with a red ring, hover backwards and forwards, almost level with
the ground. They fuss about from burrow to burrow. A few rare females
come out for a moment and then go in again.

I proceed to make an excavation with my spade; I gather indiscriminately
whatever I come across. Larvae are very scarce; pupae abound, as do
perfect insects. The list of my captures amounts to eighty males and
fifty-eight females. The males, therefore, hitherto impossible to
discover, either on the flowers around or in the neighbourhood of the
burrows, could be picked up to-day by the hundred, if I wished. They
outnumber the females by about four to three; they are also further
developed, in accordance with the general rule, for most of the backward
pupae give me only females.

Once the two sexes had appeared, I expected a third generation that
would spend the winter in the larval state and recommence in May the
annual cycle which I have just described. My anticipation proved to be
at fault. Throughout September, when the sun beats upon the burrows,
I see the males flitting in great numbers from one shaft to the other.
Sometimes a female appears, returning from the fields, but with no
pollen on her legs. She seeks her gallery, finds it, dives down and
disappears.

The males, as though indifferent to her arrival, offer her no welcome,
do not harass her with their amorous pursuits; they continue to visit
the doors of the burrows with a winding and oscillating flight. For two
months, I follow their evolutions. If they set foot on earth, it is to
descend forthwith into some gallery that suits them.

It is not uncommon to see several of them on the threshold of the same
burrow. Then each awaits his turn to enter; they are as peaceable in
their relations as the females who are joint owners of a burrow. At
other times, one wants to go in as a second is coming out. This sudden
encounter produces no strife. The one leaving the hole withdraws a
little to one side to make enough room for two; the other slips past as
best he can. These peaceful meetings are all the more striking when we
consider the usual rivalry between males of the same species.

No rubbish-mound stands at the mouth of the shafts, showing that the
building has not been resumed; at the most, a few crumbs of earth are
heaped outside. And by whom, pray? By the males and by them alone. The
lazy sex has bethought itself of working. It turns navvy and shoots out
grains of earth that would interfere with its continual entrances and
exits. For the first time I witness a custom which no Hymenopteron had
yet shown me: I see the males haunting the interior of the burrows with
an assiduity equalling that of the mothers employed in nest-building.

The cause of these unwonted operations soon stands revealed. The females
seen flitting above the burrows are very rare; the majority of the
feminine population remain sequestered under ground, do not perhaps come
out once during the whole of the latter part of summer. Those who do
venture out go in again soon, empty-handed of course and always without
any amorous teasing from the males, a number of whom are hovering above
the burrows.

On the other hand, watch as carefully as I may, I do not discover
a single act of pairing out of doors. The weddings are clandestine,
therefore, and take place under ground. This explains the males' fussy
visits to the doors of the galleries during the hottest hours of the
day, their continual descents into the depths and their continual
reappearances. They are looking for the females cloistered in the
retirement of the cells.

A little spade-work soon turns suspicion into certainty. I unearth a
sufficient number of couples to prove to me that the sexes come together
underground. When the marriage is consummated, the red-belted one quits
the spot and goes to die outside the burrow, after dragging from flower
to flower the bit of life that remains to him. The other shuts herself
up in her cell, there to await the return of the month of May.

September is spent by the Halictus solely in nuptial celebrations.
Whenever the sky is fine, I witness the evolutions of the males above
the burrows, with their continual entrances and exits; should the sun
be veiled, they take refuge down the passages. The more impatient,
half-hidden in the pit, show their little black heads outside, as though
peeping for the least break in the clouds that will allow them to pay a
brief visit to the flowers round about. They also spend the night in the
burrows. In the morning, I attend their levee; I see them put their head
to the window, take a look at the weather and then go in again until the
sun beats on the encampment.

The same mode of life is continued throughout October, but the males
become less numerous from day to day as the stormy season approaches
and fewer females remain to be wooed. By the time that the first cold
weather comes, in November, complete solitude reigns over the burrows.
I once more have recourse to the spade. I find none but females in their
cells. There is not one male left. All have vanished, all are dead, the
victims of their life of pleasure and of the wind and rain. Thus ends
the cycle of the year for the Cylindrical Halictus.

In February, after a hard winter, when the snow had lain on the ground
for a fortnight, I wanted once more to look into the matter of my
Halicti. I was in bed with pneumonia and at the point of death, to all
appearances. I had little or no pain, thank God, but extreme difficulty
in living. With the little lucidity left to me, being able to do no
other sort of observing, I observed myself dying; I watched with a
certain interest the gradual falling to pieces of my poor machinery.
Were it not for the terror of leaving my family, who were still young, I
would gladly have departed. The after-life must have so many higher and
fairer truths to teach us.

My hour had not yet come. When the little lamps of thought began to
emerge, all flickering, from the dusk of unconsciousness, I wished to
take leave of the Hymenopteron, my fondest joy, and first of all of my
neighbour, the Halictus. My son Emile took the spade and went and dug
the frozen ground. Not a male was found, of course; but there were
plenty of females, numbed with the cold in their cells.

A few were brought for me to see. Their little chambers showed no
efflorescence of rime, with which all the surrounding earth was coated.
The waterproof varnish had been wonderfully efficacious. As for the
anchorites, roused from their torpor by the warmth of the room, they
began to wander about my bed, where I followed them vaguely with my
fading eyes.

May came, as eagerly awaited by the sick man as by the Halicti. I left
Orange for Serignan, my last stage, I expect. While I was moving, the
Bees resumed their building. I gave them a regretful glance, for I had
still much to learn in their company. I have never since met with such a
mighty colony.

These old observations on the habits of the Cylindrical Halictus may now
be followed by a general summary which will incorporate the recent data
supplied by the Zebra Halictus and the Early Halictus.

The females of the Cylindrical Halictus whom I unearth from November
onwards are evidently fecundated, as is proved by the assiduity of the
males during the preceding two months and most positively confirmed by
the couples discovered in the course of my excavations. These females
spend the winter in their cells, as do many of the early-hatching
melliferous insects, such as Anthophorae and Mason-bees, who build their
nests in the spring, the larvae reaching the perfect state in the summer
and yet remaining shut up in their cells until the following May. But
there is this great difference in the case of the Cylindrical Halictus,
that in the autumn the females leave their cells for a time to receive
the males under ground. The couples pair and the males perish. Left
alone, the females return to their cells, where they spend the inclement
season.

The Zebra Halicti, studied first at Orange and then, under better
conditions, at Serignan, in my own enclosure, have not these
subterranean customs: they celebrate their weddings amid the joys of
the light, the sun and the flowers. I see the first males appear in the
middle of September, on the centauries. Generally there are several of
them courting the same bride. Now one, then another, they swoop upon her
suddenly, clasp her, leave her, seize hold of her again. Fierce brawls
decide who shall possess her. One is accepted and the others decamp.
With a swift and angular flight, they go from flower to flower, without
alighting. They hover on the wing, looking about them, more intent on
pairing than on eating.

The Early Halictus did not supply me with any definite information,
partly through my own fault, partly through the difficulty of excavation
in a stony soil, which calls for the pick-axe rather than the spade. I
suspect her of having the nuptial customs of the Cylindrical Halictus.

There is another difference, which causes certain variations of detail
in these customs. In the autumn, the females of the Cylindrical Halictus
leave their burrows seldom or not at all. Those who do go out invariably
come back after a brief halt upon the flowers. All pass the winter in
the natal cells. On the other hand, those of the Zebra Halictus move
their quarters, meet the males outside and do not return to the burrows,
which my autumn excavations always find deserted. They hibernate in the
first hiding-places that offer.

In the spring, the females, fecundated since the autumn, come out:
the Cylindrical Halicti from their cells, the Zebra Halicti from their
various shelters, the Early Halicti apparently from their chambers, like
the first. They work at their nests in the absence of any male, as do
also the Social Wasps, whose whole brood has perished excepting a few
mothers also fecundated in the autumn. In both cases, the assistance of
the males is equally real, only it has preceded the laying by about six
months.

So far, there is nothing new in the life of the Halicti; but here is
where the unexpected appears: in July, another generation is produced;
and this time without males. The absence of masculine assistance is no
longer a mere semblance here, due to an earlier fecundation: it is a
reality established beyond a doubt by the continuity of my observations
and by my excavations during the summer season, before the emergence of
the new Bees. At this period, a little before July, if my spade unearth
the cells of any one of my three Halicti, the result is always females,
nothing but females, with exceedingly rare exceptions.

True, it may be said that the second progeny is due to the mothers who
knew the males in autumn and who would be able to nidify twice a year.
The suggestion is not admissible. The Zebra Halictus confirms what
I say. She shows us the old mothers no longer leaving the home but
mounting guard at the entrance to the burrows. No harvesting- or
pottery-work is possible with these absorbing doorkeeping-functions.
Therefore there is no new family, even admitting that the mothers'
ovaries are not depleted.

I do not know if a similar argument is valid in the case of the
Cylindrical Halictus. Has she any general survivors? As my attention
had not yet been directed on this point in the old days, when I had
the insect at my door, I have no records to go upon. For all that, I
am inclined to think that the portress of the Zebra Halictus is unknown
here. The reason of this absence would be the number of workers at the
start.

In May, the Zebra Halictus, living by herself in her winter retreat,
founds her house alone. When her daughters succeed her, in July, she is
the only grandmother in the establishment and the post of portress falls
to her. With the Cylindrical Halictus, the conditions are different.
Here the May workers are many in the same burrow, where they dwell in
common during the winter. Supposing that they survive when the business
of the household is finished, to whom will the office of overseer fall?
Their number is so great and they are all so full of zeal that disorder
would be inevitable. But we can leave this small matter unsettled
pending further information.

The fact remains that females, females exclusively, have come out of the
eggs laid in May. They have descendants, of that there is no room for
doubt; they procreate though there are no males in their time. From
this generation by a single sex, there spring, two months later, males
and females. These mate; and the same order of things recommences.

To sum up, judging by the three species that form the subject of my
investigations, the Halicti have two generations a year: one in the
spring, issuing from the mothers who have lived through the winter after
being fecundated in the autumn; the other in the summer, the fruit of
parthenogenesis, that is to say, of reproduction by the powers of the
mother alone. Of the union of the two sexes, females alone are born;
parthenogenesis gives birth at the same time to females and males.

When the mother, the original genitrix, has been able once to dispense
with a coadjutor, why does she need one later? What is the puny idler
there for? He was unnecessary. Why does he become necessary now? Shall
we ever obtain a satisfactory answer to the question? It is doubtful.
However, without much hope of succeeding we will one day consult the
Gall-fly, who is better-versed than we in the tangled problem of the
sexes.



INDEX.

Alpine Odynerus.

Amadeus' Eumenes.

Ammophila (see also Hairy Ammophila).

Andrena.

Andrenoid Osmia.

Ant.

Anthidium (see the varieties below, Cotton-bee, Resin Bee).

Anthidium bellicosum.

Anthidium cingulatum (see Girdled Anthidium).

Anthidium diadema (see Diadem Anthidium).

Anthidium florentinum (see Florentine Anthidium).

Anthidium Latreillii (see Latreille's Resin-bee).

Anthidium manicatum (see Manicate Anthidium).

Anthidium quadrilobum (see Four-lobed Resin-bee).

Anthidium scapulare (see Scapular Anthidium).

Anthidium septemdentatum (see Seven-pronged Resin-bee).

Anthocopa papaveris (see Upholsterer-bee).

Anthophora (see also Anthophora of the Walls, Hairy-footed Anthophora,
Masked Anthophora).

Anthophora of the Walls.

Anthophora parietina (see Anthophora of the Walls).

Anthophora pilipes (see Hairy-footed Anthophora).

Anthrax (see Anthrax sinuata).

Anthrax sinuata.

Aphis (see Plant-louse).

Archimedes.

Augustus, the Emperor.

Bee.

Beetle.

Bembex.

Black, Adam and Charles.

Black Plant-louse.

Black Psen.

Black-tipped Leaf-cutter.

Blue Osmia.

Book-louse.

Brown Snail.

Bulimulus radiatus.

Bumble-bee.

Calicurgus (see Pompilus).

Capricorn.

Carpenter-bee.

Cat.

Cemonus unicolor.

Cerambyx (see Capricorn).

Ceratina (see also the varieties below).

Ceratina albilabris.

Ceratina callosa.

Ceratina chalcites.

Ceratina coerulea.

Cerceris.

Cetonia.

Chaffinch.

Chalicodoma (see Mason-bee).

Chrysis flammea.

Cockroach.

Coelyoxis caudata.

Coelyoxis octodentata.

Colletes.

Common Snail.

Common Wasp.

Cotton-bee (see also the varieties of Anthidium).

Crayfish.

Cricket.

Crioceris merdigera (see Lily-beetle).

Cryptus bimaculatus.

Cryptus gyrator.

Cylindrical Halictus.

Darwin, Charles Robert.

Decticus verrucivorus.

Devillario, Henri.

Diadem Anthidium.

Dioxys cincta.

Dog.

Dragon-fly.

Dryden, John.

Dufour, Jean Marie Leon.

Dung-beetle.

Dzierzon, Johann.

Early Halictus.

Earth-worm.

Earwig.

Epeira (see Garden Spider).

Ephialtes divinator.

Ephialtes mediator.

Ephippiger.

Eumenes Amadei (see Amadeus' Eumenes).

Euritema rubicola.

Fabre, Emile, the author's son.

Fabricius, Johann Christian.

Feeble Leaf-cutter.

Field-mouse.

Florentine Anthidium.

Fly (see also House-fly).

Foenus pyrenaicus.

Four-lobed Resin-bee.

Franklin, Benjamin.

Garden Snail.

Garden Spider.

Girdled Anthidium.

Girdled Snail (see Brown Snail).

Gnat.

Golden Osmia.

Goldfinch.

Grasshopper (see also Great Green Grasshopper).

Great Green Grasshopper.

Great Peacock Moth.

Green Grasshopper (see Ephippiger, Great Green Grasshopper).

Green Osmia.

Grey Lizard.

Hairy Ammophila.

Hairy-footed Anthophora.

Halictus (see also the varieties below).

Halictus cylindricus (see Cylindrical Halictus).

Halictus malachurus (see Early Halictus).

Halictus zebrus (see Zebra Halictus).

Hare-footed Leaf-cutter.

Helix algira.

Helix aspersa (see Common Snail).

Helix caespitum (see Garden Snail).

Helix nemoralis.

Helix striata.

Heriades rubicola.

Herring.

Hive-bee.

Honey-bee (see Hive-bee).

Horned Osmia.

House-dog (see Dog).

House-fly.

Kid.

Kirby, William.

La Fontaine, Jean de.

Lamb.

Languedocian Sphex.

Lanius collurio (see Red-backed Shrike).

La Palice, Jacques de Chabannes, Seigneur de.

Latreille, Pierre Andre.

Latreille's Osmia.

Latreille's Resin-bee.

Leaf-cutter, Leaf-cutting Bee (see Megachile).

Leaf-insect.

Leucopsis.

Lily-beetle.

Lithurgus (see also the varieties below).

Lithurgus chrysurus.

Lithurgus cornutus.

Lizard (see also Grey Lizard).

Locust.

Locusta viridissima (see Great Green Grasshopper).

Macmillan Co.

"Mademoiselle Mori", author of.

Manicate Anthidium.

Mantis, Mantis religiosa (see Praying Mantis).

Masked Anthophora.

Mason-bee (see also the varieties below).

Mason-bee of the Pebbles (see Mason-bee of the Walls).

Mason-bee of the Sheds.

Mason-bee of the Shrubs.

Mason-bee of the Walls.

May-fly.

Meade-Waldo, Geoffrey.

Megachile (see also the varieties below).

Megachile albocincta (see White-girdled Leaf-cutter).

Megachile apicalis (see Black-tipped Leaf-cutter).

Megachile argentata (see Silvery Leaf-cutter).

Megachile Dufourii (see Silky Leaf-cutter).

Megachile imbecilla (see Feeble Leaf-cutter).

Megachile lagopoda (see Hare-footed Leaf-cutter).

Megachile sericans (see Silky Leaf-cutter).

Melitta (see Colletes).

Miall, Bernard.

Midwife Toad.

Morawitz' Osmia.

Odynerus (see also the varieties below)

Odynerus alpestris (see Alpine Odynerus).

Odynerus delphinalis.

Odynerus rubicola.

Oil-beetle.

Omalus auratus.

Osmia (see also the varieties below).

Osmia andrenoides (see Andrenoid Osmia).

Osmia aurulenta (see Golden Osmia).

Osmia cornuta (see Horned Osmia).

Osmia cyanea (see Blue Osmia).

Osmia cyanoxantha.

Osmia detrita (see Ragged Osmia).

Osmia Latreillii (see Latreille's Osmia).

Osmia Morawitzi (see Morawitz' Osmia).

Osmia parvula (see Tiny Osmia).

Osmia rufo-hirta (see Red Osmia).

Osmia tricornis (see Three-horned Osmia).

Osmia tridentata (see Three-pronged Osmia).

Osmia versicolor (see Variegated Osmia).

Osmia viridana (see Green Osmia).

Pelopaeus.

Perez, Professor Jean.

Philanthus (see Philanthus apivorus).

Philanthus apivorus.

Plant-louse (see also Black Plant-louse).

Pompilus.

Praying Mantis.

Prosopis confusa.

Psen atratus (see Black Psen).

Rabelais, Francois.

Ragged Osmia.

Reaumur, Rene Antoine Ferchault de.

Red-backed Shrike.

Red-Osmia.

Resin-bee (see also the varieties).

Ringed Calicurgus (see Pompilus).

Rodwell, Miss Frances.

Rosechafer (see Cetonia).

Sapyga (see Spotted Sapyga).

Sardine.

Scapular Anthidium.

Scolia.

Scorpion.

Seven-pronged Resin-bee.

Shrike (see Red-backed Shrike).

Silky Leaf-cutter.

Silvery Leaf-cutter.

Snail (see also the varieties)

Social Wasp (see Common Wasp).

Solenius lapidarius.

Solenius vagus.

Sophocles.

Sparrow.

Spence, William.

Sphex (see also Languedocian Sphex, Yellow-winged Sphex.)

Spotted Sapyga.

Stick-insect.

Stizus.

Tachina.

Tachytes.

Tarantula.

Teixeira de Mattos, Alexander.

Termite.

Three-horned Osmia.

Three-pronged Osmia.

Tiberius, the Emperor.

Tiny Osmia.

Tripoxylon figulus.

Unarmed Zonitis (see Zonitis mutica).

Upholsterer-bee.

Variegated Osmia.

Virgil.

Wasp (see also Common Wasp).

Weaving Spider.

Weevil.

White-girdled Leaf-cutter.

Wolf.

Worm (see Earth-worm).

Xylocopa violacea (see Carpenter-bee).

Yellow-winged Sphex.

Zebra Halictus.

Zonitis mutica.





End of Project Gutenberg's Bramble-bees and Others, by J. Henri Fabre