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THE

LIFE OF AN INSECT;

BEING

A HISTORY OF THE CHANGES OF INSECTS FROM THE
EGG TO THE PERFECT BEING.


PUBLISHED UNDER THE DIRECTION OF

THE COMMITTEE OF GENERAL LITERATURE AND EDUCATION,

APPOINTED BY THE SOCIETY FOR PROMOTING

CHRISTIAN KNOWLEDGE.


LONDON:

PRINTED FOR THE

SOCIETY FOR PROMOTING CHRISTIAN KNOWLEDGE;

SOLD AT THE DEPOSITORY,

GREAT QUEEN STREET, LINCOLN'S INN FIELDS,

AND 4, ROYAL EXCHANGE;

AND BY ALL BOOKSELLERS.




LONDON:

R. CLAY, PRINTER, BREAD STREET HILL.




CONTENTS.


PART I.--THE EGG.

                                                                  PAGE

  Chapter I.--_The Nest._--The Microscope and Telescope--Terror
      caused by Insects--Death-watch--Life-boat of Eggs--The
      Water Beetle--Floating Ark of Eggs--The Gnat--her
      difficulties--her Egg-raft--The Sand-boring Wasp--Towers
      of rubbish--Captive Caterpillars--Wood-boring Bee--An
      Insect Nursery--Escape of the young--Tapestry Bee--A Nest
      lined with Poppy-flower Petals--Enchanted Leaf-tubes--The
      spell broken--The Insect Sorcerer--Nest of Down made by a
      Moth--The Lackey Moth--The Ichneumons--Their usefulness        1

  Chapter II.--_Structure and contents of the Egg._--Its
      Shape--Remarkable mistake about an Insect--The
      Lace-wing Fly--Eggs carved on their surface--Colours of
      Eggs--Changes of Colour--Eggs of the Garden Spider--Pretty
      Nests--Anatomy of the Egg--Contents of the Egg                43

  Chapter III.--_Life begins in the Egg._--Spring
      Time--Influence of Heat and Cold--Eggs resist great
      Cold--The time of Hatching--Escape of the new
      Creature--Connexion between Plants and Insects--Changes
      in the Egg--A Spider's Mother's love--Experiment with two
      Spiders--Anecdote of an Earwig--Enormous number of Eggs of
      different Insects                                             57


PART II.--THE LARVA.

  Chapter I.--_The Young Larva._--Affection of a Field-Bug--An
      Earwig Mother--Anecdote of a Spider--Ant-Nurses--Varieties
      of Larvæ--The Larva born--Forms of Larvæ--Larvæ of
      Butterflies--Structure of a Larva                             79

  Chapter II.--_Habits of the Larva._--The Lion of the
      Aphides--its Courage--The Ant-Lion--The "Giant Grim" of
      Insects--Formation of its Trap--An Insect Excavator--The
      Den--A Stone in it--A captive Ant--Principle of
      Compensation--The Sand-Wasp's Den--A Warrior-Wasp--An
      Insect Duel--The Kakerlac and the Bandit Wasp--The
      Corpse carried home--A Wasp clad in the Wings and
      Limbs of Insects--The Tiger Beetle Larva--Dragon-Fly
      Larva--its curious Mask--a ferocious creature--Ravages of
      Cockchafer Larvæ--Lamp Oil got from Larvæ--"Old Father
      Long-legs"--The Gamma Moth and its Larva--Magical Origin
      of--The excessive numbers of the Larvæ--Destruction of
      Trees by Larvæ--Killed by rain--The Weevil--Insects on
      board Ship--Appetite of Larvæ--Silk-Worm Larva--Larvæ
      enormous Eaters--Growth of Larvæ                              93

  Chapter III.--_Moulting of the Larva._--Escape of Larva
      from its old Skin--Arrangement of the Hairs--Danger
      attending the Moult--Colours of Larvæ--Influence of
      Sun-light--Curious appearance of the Coats of Larvæ--Larvæ
      like Twigs--Singularly coated Larva                          146

  Chapter IV.--_Respiration of the Larva._--Experiment
      with Larvæ--Insects do not breathe by their
      Mouths--Breathing Mechanism of Larvæ--Spiracles--Aquatic
      Larvæ--Inhabitants of the Ditch and Pool--Rat-tailed
      Larvæ--Remarkable Organ--Chameleon-Fly Larva--Larva of
      the May-Fly--Their under-water Cells--Singular organs of
      Respiration--Complete Armour of Dragon-Ely Larva             157

  Chapter V.--_Means of Defence of the Larva._--Leaf-dwelling
      Larvæ--Larva clad in Rags--"Hickory-horned Devil"--Larva
      with a Squirt--Shaggy-coated Larvæ--Frozen
      Larvæ--Dwellings of Larvæ--Remarkable Australian Larva
      cases--Larvæ in Winter                                       178

  Chapter VI.--_Preparation for a Change._--Age of the
      Larva--its attempts at concealment--Cocoons of
      Larvæ--Silk-Worm Cocoon--Extraordinary precaution of a
      Larva--Case of Bark-skin--Anecdote of a Larva--Suspension
      of the Larva, horizontally and perpendicularly--Larva of
      Meat-Fly--Last action of the Larva                           194


PART III.--THE PUPA.

  Chapter I.--_The Transformation._--Meaning of the word
      _Pupa_--Various names of Pupæ--Process of the
      change--Remarkable feat of a Pupa--Time occupied in the
      Change                                                       213

  Chapter II.--_What is a Pupa?_--Characters of a Pupa--Active
      and Inactive--Dissection of a Pupa--Contents
      of Pupa-case--Singular Pupa--Goedart's strange
      Representations of Pupæ--Pupæ from Surinam--Colours of
      Pupæ--Aurelia and Chrysalis--Ground Pearl                    225

  Chapter III.--_Respiration of the Pupa._--Spiracles
      of Pupæ--Anecdote from De Geer--Air-Cell under
      Water--Difficulty of the task--Pupæ with an Air-tube         239

  Chapter IV.--_Varieties and Age of the Pupa._--Different
      kinds of Pupæ--Age of the Pupa--Pupæ hatched in a
      Hot-house--Butterflies in Winter--Pupæ hatched by a
      Hen--Glass Eggs--Influence of Warmth and Cold--Dreams
      of Immortality--Réaumur's mistake--Varnishing
      Pupæ--Preservation of Eggs--Falling of the "Manna"--Final
      changes of the Pupa                                          251

  Chapter V.--_The Great Change._--An Insect Prisoner--Escape
      of the Cossus--Escape of a Fly--A guide-line
      to the Captive--Cocoon of Emperor Moth--Escape
      backwards--Chemical solvent--Escape of Ants--Huber's
      Ant-hill--Assistant Ants--Aquatic Insects--The
      Caddis-worm--Singular escape--The Gnat--A time
      of Peril--Blood-Worms--A curious spectacle--The
      Dragon-Fly--Phenomena of the Change--The Insect
      new-horn--Curious facts about Pupæ                           273


PART IV.--THE IMAGO.

  Chapter I.--_The New-born Perfect Insect._--The
      Resurrection--Meaning of the word Imago--Curious aspect
      of New-born Insect--Conclusion of the Dragon-Fly's
      History--Structure of a Wing--how expanded--Deformed
      Wings--Exception in the Ephemeræ--Dance of the
      Ephemeræ--Insects without Wings--Showers and Stains of
      Blood--Aphis-Lion Fly--Insects in the Imago state do not
      increase in size                                             309

  Chapter II.--_The Structure and Organs of the Imago._--Anatomy
      and Physiology--Insects have not Bones--Leather-coated
      Jack--The Head and Thorax--The Eyes--simple and
      compound--Wonders of an Eye--Anatomy of the Eye--Immense
      number of Eyes--Remarkable Provision--Experiments on the
      Eyes of Bees--Beauty of the Eyes--The _Antennæ_--their
      Function, perhaps the Nose--Insects Weather-wise--Insects
      in Rain--Organs of Speech--Anecdote of Bees--Various
      Functions of Antennæ--The Mouth in Insects--Parts of
      the Mouth--Spiral Tube of the Butterfly--Taste and
      Smell in Insects--The Trunk--Wings--Membranous--Scale
      covered--Wing-Cases--Experiments on Flying--Painted
      Wings--The glory of the Butterfly--The Legs
      of Insects--Cleanliness of Insects--The Water
      Boatman--Kangaroo Beetle--The Abdomen--The Sting of the
      Bee--Insect with a Leg in its Tail                           335

  Chapter III.--_Respiration of the Imago._--Experiments upon
      the Breathing of Insects--Chloroform--Coal-gas--their
      Effects--Contest between a Spider and a Blue-Bottle
      Fly--Air-Pipes of Insects--Multitude of Air-Tubes--
      Circulation of Blood in Insects--An Insect's Pulse           398

  Chapter IV.--_Food and Death of the Imago._--Vegetable
      Eaters--Carnivorous Insects--The Tigers to Insects--Fasts
      of Insects--The Last Duty--Insect Forethought--The
      Creator's Wisdom and Love--God does not despise Little
      Things                                                       408




ILLUSTRATIONS.--DIRECTIONS TO BINDER.


  Egg-rafts of the Gnat                                              1

  Ferocious Larvæ of Dragon-Fly                                     79

  Insects escaping from the Pupa condition                         213

  Evening Flight of Ephemeræ                                       307




THE LIFE OF AN INSECT.




PART I.--THE EGG.




CHAPTER I.

THE NEST


To look at a house-fly as it performs its figure-of-eight dances
in the air of our rooms, or as it buzzes against the window-pane,
vainly endeavouring to dash its tender body through the firm and
clear glassy wall--to mark how soon it comes into existence, and how
soon its little day of life is gone--one would say it is a foolish
and trifling thing to write the history of an insect's life; but any
one who would thus speak must be ignorant of that which he declares
to be folly and trifling. He cannot know the miracles of skill that
insects, insignificant as they seem, are capable of performing; nor
the astonishing lessons of wisdom which even man may learn from these
minute and short-lived beings. So long as we are ignorant of any part
of God's creation, we may very probably think light of it; but when
we come to inquire into the things we have formerly despised, and
will give a patient attention to what we before thought beneath our
notice, the tone of our remarks will greatly alter. Now, we shall find
in the meanest things formed by the Divine hand inexhaustible themes
for wonder and praise, and innumerable proofs that the great Almighty
power which built our round world, and countless worlds besides, which
fixed them with a firm decree in an appointed course, has not been less
displayed even in the formation of a tiny insect, which is this hour
alive, and the next lost to being.

The telescope shows us what God has created in the innumerable millions
of stars and suns which every clear night look down with gentle beams
upon the earth; it shows us that the earth on which we dwell, compared
to the worlds by which it is surrounded, is as a grain of sand to a
mighty mountain. But the microscope, on the contrary, shows us what
is almost more wonderful even than this; for it shows us that though
the High and Lofty One who inhabits eternity has created all these vast
systems of suns and stars, yet he has not thought it beneath Him to
chisel the egg of an insect or to adorn the coat of a tiny caterpillar.
Well might we pause and ask as we look now through the wonder-revealing
tube of the microscope and then through that of the telescope--Was it
not a greater evidence of power and wisdom to create, clothe, organize,
and endow with the powers of life, a little atom which we can detect
only by means of a powerful microscope, than to form even a great and
mighty world? For our part, then, we think an insect's history as
much a display of the wisdom and infinite power of the Creator as the
history of such an enormous body as is the sun, or any of the large
planets belonging to our system. However humble be the object which
God has seen fit to create, let not any one think it beneath _him_ to
examine. The poet Thomson has written some pretty lines which we shall
venture to transcribe, which, with far greater beauty of language than
we can pretend to, set before us the same train of thought:--

    "Let no presuming impious railer tax
    Creative wisdom, as if aught was formed
    In vain, or not for admirable ends.
    Shall little haughty ignorance pronounce
    His works unwise, of which the smallest part
    Exceeds the narrow vision of her mind?"

Animals, birds, reptiles, fish, and plants, have had their biographers,
and ponderous books have been written to give us an introduction to
their various families: so also have insects; although despised by
many, they have been highly esteemed by a few; and if honours went by
the size of books written about them, it might perhaps be shown that
the insects can boast of great and closely-printed books taken up with
nothing else but an account of them and their doings.

Perhaps there is another feeling about insects which ought to be
mentioned beside the feeling of contempt; that is, the feeling of
aversion. A great many people, ought we to write? a great many ladies
and children, are ready to scream, and take to their heels if they see
a poor "black beetle," racing in terror of his life for fear of _them_,
and as both parties are equally frightened of one another it becomes
very difficult to manage a reconciliation between them. At the sight
of spiders some people are ready to faint away, and to see a little
caterpillar creeping along with his magnificent coat of parti-coloured
hairs, and with that funny gait which it is quite ludicrous to behold
as he binds himself into a loop and walks after a fashion like no other
earthly being, is enough to make their hair stand on end and their
flesh to creep!

[Illustration: _Death's-head Moth._]

Sometimes insects are the innocent causes of alarm even to nations.
Thus there is a peculiar kind of moth, upon the back of which there
is very distinctly marked the appearance of what is vulgarly called a
"death's head," its name being the death's-head hawk moth, represented
in the adjoining cut, which was once the cause of the greatest terror
to a number of persons. It was in Bretagne that a large flight of them
suddenly made their appearance; at the same time a dangerous epidemic
disease fell upon the inhabitants; the awful look of the poor insect,
together with its strange supernatural noise, filled the ignorant
people with alarm, and the disease was considered to be actually caused
by the moths. Another insect, the church-yard beetle, which is of a jet
black colour, is related by the great Linnæus as producing the most
alarming feelings upon the minds of the superstitious and ignorant
among the peasantry of Sweden.

The death-tick beetle has also a terrible reputation for frightening
people. This little creature takes up its abode in decayed wood, and
thus frequently makes the bed-post its dwelling-place, or ensconces
itself in the wainscot of an old room. Now, when, as some entomologists
tell us, it wants to give a signal to its mate, the insect begins
hammering with all its might at the side of the wall, or knocks upon
its little floor until the noise is heard, and the mate then begins to
hammer, both producing for their size a tremendous noise, but in human
ears not sounding louder than the tick of a large watch. The poor
invalid, as he lies in bed perhaps very nervous and unable to bear loud
conversation, hears the noisy insects knocking one to the other, and
immediately his mind is filled with fears of the most groundless kind,
which the nurse, if she is one of the old school, is sure to confirm by
telling him that this ticking is the death-watch.

[Illustration: _Death-watch Beetle._]

All this is not only very weak and foolish, but when it reaches the
degree to which we have here referred, it is also very wrong. As to
the death's head hawk moth producing disease or foretelling death
and famine, as it has been said to do, how weak and credulous must
they be who draw such omens from a mark on an insect's head; and how
dishonouring is it to the all-wise providence of God to imagine that
he would suffer such a ridiculous emblem to have any such actual
signification! The little beetle which produces the ticking sounds was
caught by Dr. Derham one fine sunshiny day, tapping as loudly as it
could on a piece of paper in a window; he examined the little creatures
and kept them carefully, and he states that during the whole of one
summer they scarcely ever ceased tapping night and day. Birds have
their calls to their companions, and animals have theirs, yet we do
not draw from these the wild supposition that they foretell death or
such like disasters. Why, then, should the love-tap of an insignificant
beetle have received such an interpretation? It is hard indeed to tell.

Now all these feelings about insects, contempt, abhorrence, and
terror, arise in one common cause, and that is ignorance. A very
small acquaintance with the contents of the little work upon which
we are now entering, would suffice to dispel them all. It may be,
perhaps, difficult to overcome what is called a "natural aversion"
to any object, especially to an unfortunate insect; but when it is
overcome, and when we learn, for the first time, all the extraordinary
actions, habits, and instincts, of this portion of the great creation,
admiration will take the place of contempt, and even a humble sort of
affection that of the terror and aversion produced by them before.

With the reader's permission, then, we will proceed to take him with
us as we describe the various stages of the Life of an Insect, from
the egg up to the perfect being. It may be, however, just necessary to
premise that in so doing we shall not give anything like the history of
an individual insect, such, for example, as a fly or a bee; but shall
describe in order some of the most interesting phenomena connected with
insect-history and transformations generally. Whither, then, must we go
to watch the awakening of life in the insect? We might ask the reader's
company to

                    ----"where the pool
    Stands mantled o'er with green, invisible
    Amid the floating verdure, millions stray."

Here might we point to him that wondrous and exquisite structure, the
life-boat of eggs, floating[A] securely on its silent surface, or
anchored, perhaps, to the side of some pond-plant's slimy stem; and
lingering here we might in a few days see the little eggs become burst
and give exit to a number of minute creatures of great activity. Some
of them would be seen twisting themselves about in a most extraordinary
manner, and swimming here and there through the still waters. Or we
might take him to the depths of the forest, and now, under the bark of
some of the trees, now upon their branches, now in little tents of
leaves, we could point out many a colony of eggs only waiting for the
life-giving influence of spring to burst into life and activity.

But it is better for us to proceed more systematically, and to notice
shortly the interesting facts which the science of entomology reveals
to us as to the egg-cradles, so to speak, of insects, by which is meant
the various localities selected by them for the deposition of their
eggs, some of them, as we have mentioned, in the water, some in the
earth, some upon plants and trees, and some in mansions made by the
insects themselves for the purpose of hatching their eggs.

Let us come, then, and watch the great water-beetle, at the time when
the mother-insect is about to commit her future offspring to the
care of the waters. She is to be found on fine days, when the sun is
going down into a bed of gold, enjoying herself and delighting in
the pleasant air of the evening, as she sits upon a plant close by
the water's edge; or she may even have taken up her position on a
floating leaf of the plant, the clear waters flowing gently beneath
her. She has been in the water all day long, and is now just emerged.
On other evenings she will take wing, and speed her way whither no
eye can follow; but now, she has another and the most important duty
of her existence to perform, and her customary evening ramble is not
permitted to interfere with its fulfilment. On watching her closely we
find her busy at some self-imposed occupation; what is its nature? To
discover that, she must be closely and patiently watched. At her tail
are a couple of spinning organs, which move from right to left and up
and down with great swiftness, all the while a glutinous fluid, which
hardens into a thread, being discharged from each of them. With this
apparatus the industrious insect is spinning a pouch not unlike the
purses which were in fashion before the long ones that ladies knit
came to be adopted. This purse is three quarters of an inch long; it
consists outside of a tissue, like parchment, which is quite impervious
to water, but is lined inside with the most beautiful, light, downy
material possible, which is as white as snow. There is a sort of little
horn to this pouch, which admits the air, but the opening to which
is protected by a layer of cross threads, which excludes the wet. In
three hours of patient toil this beautiful cradle is completed. The
water-beetle then safely secures it from being carried away by the
waters on which it floats so buoyantly, by fastening it by cables to
the neighbouring plants. Here safely moored it rests until the eggs are
hatched, soon after which the little creatures within escape into the
waters out of the ark, which has, during the period of their infancy,
safely preserved them from every danger, both of water and wind.

The proceedings of the common gnat, our summer tormentor, are no less
interesting and instructive. Her actions have been closely watched by
the great Réaumur, and are detailed by him with very striking accuracy.
They require, perhaps, sharper scrutiny than most of our readers
are in the habit of bestowing upon the actions of insects, but they
well repay a patient and attentive observation, and subjects for the
examination may easily be found at the side of any pool in summer.
The following is an outline of the difficulties the insect has to
contend with in depositing her eggs. First, they must be hatched on the
water; but, 2d, her eggs are heavier than water, and will therefore
sink if dropped into it one by one; and, 3d, the eggs are so small
and of so peculiar a shape that it would be difficult to make them
stand upright on a solid surface; far more so then, on the water. A
human ship-builder would be probably sorely puzzled to find out how to
overcome these difficulties, and of such materials how to construct a
floating raft; nay, a raft which cannot by any means be made to sink.
The insect has, however, been instructed by a Greater and Wiser than
man, and she solves the problem in a manner well calculated to excite
our admiration and praise. Fixing herself by her four front legs upon
a leaf or twig floating on the surface of the water, she stretches
out behind her the two hind legs, and crosses them over one another
somewhat in this manner [Illustration]. In the triangular space thus
formed she purposes to construct her boat of eggs. Now, all things
being ready, just where the crossed legs meet she places her first
egg, which is covered over with a thick glue. By the side of this she
places another, and again another, so that the three are, by means of
the glue which covers them, united together, and will, consequently,
preserve the upright position, as there is now a sufficiently broad
base of support for them to rest upon. To these she diligently adds egg
to egg until she has sufficiently formed the shape of her boat; after
which she uncrosses her legs and places them quite straight, so as to
shape the sides of the boat. When a sufficient number of eggs have been
thus glued together, the number varying from two to three hundred, the
gnat considers her task as ended, and wings her way from the pool,
abandoning her ingenious structure to the mercy of wind and wave,
although not without the security of knowing that neither wind nor wave
could commit serious injury upon it.

"In shape," write Messrs. Kirby and Spence, "this little boat pretty
accurately resembles a London wherry, being sharper and higher, to use
a nautical phrase, _fore_ and _aft_; convex below and concave above;
floating, moreover, constantly on the keel or convex part. But this,"
they add, "is not all; it is, besides, a _life-boat_, more buoyant
than even Mr. Greathead's. The most violent agitation of the water
cannot sink it; and what is more extraordinary, and a property still a
desideratum in our life-boats, though hollow it never becomes filled
with water, even though exposed to the torrents that often accompany a
thunder-storm. To put this to the test I yesterday placed half a dozen
of these boats upon the surface of a tumbler half full of water. I
then poured upon them a stream of that element from the mouth of a
great bottle held a foot above them, yet, after this treatment, which
was so rough as actually to project one out of the glass, I found them
floating as before upon their bottoms, and not a drop of water within
their cavity."

[Illustration: _Rubbish Towers of the Sand-Wasp._]

Some insects make the homes of their young in the earth. Of these,
the insect called the sand-wasp forms, perhaps, one of the most
interesting examples. This insect selects generally a hard sunny
sand-bank for the excavation it is about to accomplish. Armed with
a pair of powerful jaws, by means of which the insect can break off
good-sized fragments of the rock she is about to mine, she sets to
her arduous undertaking with a bold heart, and it is not long before
a tolerable cavity is scooped out. Many of our readers have seen the
manner in which human miners proceed when they are forming a hole
in a lime or other rock, for the purpose of blasting, and must have
noticed that they are in the habit of using a little water, in order
to facilitate the boring operation. We are all, also, familiar with
the tale of Hannibal chemically softening the Alpine rocks by means
of vinegar. The little insect in question has been instructed by the
great Creator also to adopt a means of shortening her labour, for it
has been observed that she moistens the rock by letting fall a drop or
two of fluid upon it from her mouth. By this means her work goes on
rapidly. The rubbish soon begins to accumulate. It will be scarcely
conjectured what this patient labourer does with it. Were we to look
narrowly at the sand-bank which such wasps frequent, we should find on
its surface a number of curious little projections like horns, rising
from the surface. These are towers built by the sand-wasp of the
pieces of rubbish which she scoops out of her mine. She cements them
together, and, instead of throwing them away, she lays the masses in
regular order until they have assumed the appearance here shown. It
has been supposed she does this with a view to keep out enemies and
to keep her progeny cool; just as in a tall house the cellar is its
coolest apartment, so the height of the tower in question seems to be
an additional protection against the rays of the scorching sun. After
it has deposited its egg at the bottom of the excavation, the sand-wasp
sets out on a foraging expedition, and hunts about until she finds
certain green caterpillars. Seizing upon one of these she flies with it
to her mine, and then returns for more prey. After collecting about a
dozen of these helpless beings, fixing them so that they are hopeless
captives inside her dark prison, she bids farewell to the egg, for the
future well-being of which she has thus assiduously provided. She takes
down her tower of stones, and, with the materials which composed it,
fills up the entrance to the cell, thus shutting in both the prisoners
and their future devourer in a common dungeon, there to await the
changes which time will inevitably bring about.

Let us speak now of eggs carefully deposited by other insects in
galleries and excavations made into timber. The insects which thus act
have been called by the fanciful title of carpenter-bees, in allusion
to the drilling process by which they penetrate the wood. A highly
interesting spectacle it is, in truth, to see one of these pigmy
carpenters at her work, and, fortunately, some of the species are not
very uncommon in our gardens. Spring is the season when she commences
her labours. She reconnoitres about for a proper piece of timber for
some time, and exhibits great discrimination in the selection of a
suitable place for establishing herself and for the nurture of her
progeny. Strange to say, she will not select living wood, such as the
trunk of a tree, but generally prefers wood which has already begun
to decay, as if fully aware that such wood was likely to give her
much less trouble in boring than any other. She also selects a piece
of wood placed in some sunny and genial position, with a view to the
development and comfort of her progeny. This important point being
settled to her mind, she next sets about the work. Well may Réaumur
exclaim, "Truly the labour she has undertaken demands strength,
courage, and patience!"

[Illustration: _Carpenter-Bee._]

[Illustration: _Mandibles of the Carpenter-Bee._]

The violet carpenter-bee is, perhaps, the most interesting example
we can select. She begins by cutting out with her strong jaws small
portions of the timber, and soon forms a little hole, which looks
downwards and inwards into the wood. She then alters the direction of
her drilling, and now perforates the timber perpendicularly downwards,
and in a parallel direction to the sides of the wood. Long and hard
does she thus labour, until she has actually scooped out a tunnel
in the timber a foot or so in length, and half an inch in diameter.
Sometimes she will drill several of these beautiful galleries in the
wood. The task, however arduous, never seems to weary her; impelled by
a heaven-bestowed influence, she works strenuously and cheerfully for
weeks, or even sometimes for months. Our readers may be interested
to know what she does with the saw-dust. If they can but get an
opportunity of watching her they will soon see her mode of dealing with
it. Standing by the side of the wood she is drilling, and keeping our
eyes stedfastly fixed on the hole, we shall presently observe her head
emerging from it, and immediately after she is seen to shovel out a
little heap of the dust, which accumulates on the ground beneath into
a pile. When her galleries are finished her labour is yet far from
accomplished. She has now to deposit her eggs, and make provision for
the prospective wants of her young ones. Now, her eggs must not be
piled together, nor be scattered about in the same cavity. The larvæ
which are to be produced by them must each live in separation from
the others. How is this fresh difficulty to be overcome? The insect
soon supplies us with the answer. She has not forgotten her heap of
saw-dust. She first deposits an egg at the bottom of the tunnel, and
then away she flies to the fields for a load of the fine yellow dust of
flowers, called _pollen_, and also for honey. She mixes these up into
a nice little mass of pollen-bread, or cake, which is intended for the
food of the larva, when it comes out of the egg, and then piles it up
in the gallery just over the first egg. She then, at a height of about
three quarters of an inch, plasters a layer or ring of saw-dust made by
her into a sort of mortar, and adds to this another and another ring
of the same material until the ceiling is quite complete, and the cell
thus formed is shut off from the rest of the excavation by a circular
plate of this substance, which effectually excludes all intercourse
between the occupants of this wooden nursery. Having completed this
cell she proceeds in the same way to lay an egg, and to provide a
store of food, and, finally, to close in the rest of the gallery,
until she has subdivided it into ten or twelve separate apartments.
The appearance of the circular ceilings formed on these ingenious
principles is exhibited in the engraving annexed.

[Illustration: _Cells of Carpenter-Bee._]

[Illustration: _Ceiling-plate._]

[Illustration: _Section of Cells, showing the ways of escape._]

One of the most striking facts in connexion with the proceedings of
this little creature has yet to be brought under our notice. It will
be readily admitted that the first egg deposited at the bottom of the
gallery will be the first, in point of time, that will be hatched, and,
consequently, the first to require to make its escape from the wooden
prison-house of its birth. How is it possible for this to take place,
when above the poor prisoner's head are ten or twelve cells full of
other occupants, and each shut in with a hard ceiling and floor? By
referring to the figure, we obtain a clue to this enigma. It is here
seen that there are holes which communicate with the tunnel within.
The uppermost of these holes was the one by means of which the tunnel
was first formed, but the two lower ones have been expressly formed by
the carpenter-bee to provide against the dilemma in which her young
would otherwise have been placed. They form as it were posterns or back
doors by which, when the insect is perfected, it is easily enabled to
make its escape. Singular, indeed, it is, that the insects, previous to
passing into their last transformation, arrange themselves with their
heads downwards, so that every one of them generally emerges at the
so-called back-door of the mansion.

There are many similar instances in natural history of the manifest
wisdom and forethought of the Creator of all things, visible and
invisible, but we may safely say there are not many which show it in
so clear and striking a point of view as this. It is to be remembered
this industrious insect in the arrangements in question does not act
from past experience. She never saw her young brood, nor could learn of
herself their wants and dispositions, yet her plans for their welfare
are as admirably contrived as if she had brought up generation after
generation under her own eye, and had learnt wisdom by the lapse of
years. Plainly, therefore, her actions are all directed by an impulse
given her from God, and we may well exclaim with the wise king of
old, it is God who "doth instruct her to discretion, and doth teach
her." Altogether, what an example of patience and cheerfulness in her
labours, and of admirable wisdom in their performance, is presented to
us by this little sketch of the history of the carpenter-bee's nest!

Among the birds discovered in Australia, is one called the Bower-bird,
from its fondness for making a bower, which it ornaments in a very
pretty manner. Other instances of a somewhat similar kind could be
mentioned, tending to show that some of the lower animals are as fond
of decorating their dwellings as we are ourselves. There is, however,
in the insect world, a little creature which has been called the
tapestry-bee, which adorns the place where its progeny is to be born
with a tapestry as novel as it is elegant. The great entomologist whom
we have before quoted, thus describes his first discovery of this
interesting fact:--"In one of my rambles, which had led me through
several lanes, and in the course of which I had frequently stopped to
examine the little tunnels pierced in the earth by various insects, my
companions began to engage in the same occupation with myself; one of
them at length perceived, and pointed out to my notice, a tunnel which
had some peculiarities of appearance not possessed by the others we had
seen; its interior seemed to be painted with vermilion. A small twig
was immediately gently pushed into it, and with a knife we carefully
removed the earth which surrounded it, taking great care not to injure
the walls of the tunnel. When we had uncovered it sufficiently, it was
found that the little stick was buried in a tube made of the leaves of
the field poppy.

[Illustration: _The Tapestry-Bee and its Cell._]

"I need scarcely say, that during the remainder of our ramble we were
exclusively occupied in searching for similar holes. It is a common
observation, that when a fact, which has not hitherto been recognised
among those presented to us in nature, is once caught sight of, we are
almost sure to see it again and again, until we wonder how it could
have been that it was never noticed before. We therefore now found
other holes, leading to similar tubes, formed in the same manner of the
flowers of the red poppy. Altogether, before returning home, we found
seven or eight of them; and since that time, I have found them in all
their different stages." These elegantly decorated apartments were
subsequently found to belong to the tapestry-bee.

[Illustration: _Poppy-flower cut by the Bee._]

This bee, in forming the future abode of her young, begins by scooping
out a burrow in some pathway, which she bores to the depth of two
or three inches. She then smooths the walls of this cavity, and all
being now ready for putting up the hangings, she betakes herself to
the fields, and alights upon some fresh-expanded poppy flower, just
displaying its crimson cheeks to the light of day. Here she quickly
plies the scissors which she has been armed with for this purpose,
and in a very short time cuts out of the bright petal on which she
rests, a smooth portion of a definite size. She then returns home,
and, by means of the scissors and her legs, she cuts and smooths the
piece until it lays quite flat upon the bottom of her cell. This done,
she flies for more, and in a short time, could we peep in, we might
find her mansion all over-spread with tapestry, more bright in colour,
and more delicate in point of finish and texture, than human art can
by possibility produce. The apartment being thus not only decorated,
but rendered, both to the eye and senses, warm and comfortable, she
then stores up in it a quantity of pollen and honey, until she has
filled it to the height of half an inch, when she deposits the egg,
for whose wants and, as we might say, even luxuries, she has thus
elegantly provided, folding some of the hangings carefully over it. The
remainder of the cavity is filled with loose earth. We have taken it
for granted, in this account, that the insect really takes a pleasure
in the brilliant colours with which she ornaments her cell; but it is
only right to say, in addition, that we have, of course, no positive
proof that such is really the case. For aught we know, her motives may
be very different; it is, however, an amusing way to consider these
actions, be the explanation of them what it may.

[Illustration: _Finished Cell._]

We fear, however, we dare not promise our readers the same success
as that which attended M. Réaumur and his companions. It has been
thought, that this interesting insect is not a native of our island,
and it is certain it has not been commonly observed amongst us; but Mr.
Rennie, in his work on Insect Architecture, says, that at a beautiful
sea-bathing village in Ayrshire, he once found in a footpath a great
number of the perforations of the tapestry-bee. At all events, they
deserve looking for.

[Illustration: _Leaf tubes._]

Although we have, perhaps, lingered long enough over the insect cradle,
we must spare room for one or two more remarks on this subject, and
it were almost a shame, while speaking thereon, to omit a notice of
one of the most elegant cradles of all--one made with rose-leaves! As
Réaumur's account of the manner in which he first became acquainted
with these egg depositories is very pleasantly written, we shall
extract the substance of it from his work. It was one day in July,
1736, that a gentleman of rank, accompanied by his suite and his
gardener, who was in a state of great alarm, waited upon an eminent
naturalist in Paris. The gardener had left his master's country-seat,
near Rouen, to proceed with all haste to the metropolis, in order to
communicate to his master the terrible tidings, that his ground was
bewitched! He had the courage, however, to pick up the spells, or
charms, which the sorcerer had placed in the earth, and to carry them
to his master, in full belief that they were sufficient to convince
all the world of the reality of the enchantment. He had, indeed,
in the first instance, taken them to the parish priest, begging his
counsel, and both came to the same conclusion--that, without doubt,
the garden was now enchanted ground! When the gentleman saw the little
things his gardener called charms,--which are here represented,--he
was much perplexed, although his good sense led him to ridicule the
idea of the bewitchment of his property by such means. He applied to
his medical adviser for a solution of this problem; but, alas! he was
no entomologist, and could not enlighten him; but he directed him
to the naturalist of whom mention has been made, and whose name was
M. Nollet. On being admitted to the presence of this gentleman, the
terror-stricken gardener hastily put on the table the little rolls
of leaves he considered to be spells, and which had been made, with
some evil design, as he doubted not, by the malevolent hands of some
sorcerer. Fortunately, M. Nollet had in his museum some rolls of leaves
formed with equal art by beetles; he produced them, and showed them
to the affrighted man, assuring him, that, without doubt, they had
been formed by insects, and that it was therefore highly probable that
the rolls in question were the productions of some other insects of a
different species. The gardener looked incredulous, being apparently
unwilling to give up his alarm, until M. Nollet, greatly to his horror,
took up one of those little leaf-rolls which had caused him so much
uneasiness, and carefully unfolding it, drew from thence a fat little
larva. The moment the gardener saw the little creature, his fears and
troubled aspect vanished, and an air of cheerfulness spread over his
face, such as one might imagine as the result of deliverance from some
fearful peril. The only reward M. Nollet would receive from the poor
man for thus dissipating his cares and fears was, that he should leave
the leaf-rolls with him, and, collecting more of them, should send
them to M. Réaumur's address, for him to examine. This little anecdote
affords us a good illustration of the connexion of superstitious fears
with ignorance on points of natural history, and sets before us, in
well-relieved contrast, the foolish terrors of the unlearned gardener
with the collected bearing of the learned naturalist. Would that this
anecdote stood alone in the records of natural history! We have already
seen that it does not; and that the most groundless apprehensions have
taken their rise in the most innocent and trifling of natural causes.

[Illustration: _The Bee with a leaf cut._]

By and by, after a little careful investigation, the true artificer of
these spells was discovered, and proved to be a lowly insect, which
has been since called the rose-leaf-cutter bee. On closer examination,
these rolls of leaves,--which are almost as long and as large as a
tooth-pick case,--were found to be made up of six or seven cells,
each separate from the rest, placed end to end, and covered with a
common coating of leaves. The manner in which the roll is formed is as
follows:--The insect sometimes makes a perforation in decayed wood,
sometimes in the well-trodden earth of a footpath; this she drives to
the depth of, perhaps, nine inches, and she then proceeds to hang this
apartment with its green tapestry,--for it must be understood, it is
not the leaves of the flower, but of the stem of the rose-tree,--or,
in other words, the green leaves, that she selects for this purpose.
The insect alights upon what she considers to be a suitable leaf, and
begins with her sharp jaws to cut out a piece of a crescent form from
its edge. When she has cut, perhaps, half-way round, or rather more,
she sets her wings in motion, so as to keep her balanced in the air,
lest she should drag away the half-cut piece before it was properly
divided from the leaf. When cut, she places it in a perpendicular
position between her legs, and flies away with it to her cell. She
then simply folds it into a proper form, and overlays the cell walls
with this leafy covering, not using any cement to make it retain its
form, but relying upon the natural elasticity of the leaf to keep it
close pressed against the wall in the manner in which she places it.
Repeating this process several times, she finally completes each cell
with exquisite art and care, and taking the precaution of arranging
all her joints and seams so that they shall not present themselves
in the same place, but covering them over with pieces of leaf, so
as to strengthen them, and in many other respects exhibiting an
amount of mechanical and mathematical skill never sufficiently to be
admired, she now deposits the minute egg in it which is to become the
toilsome, busy, patient, and clever being,--the full-grown insect of
her own species. Mindful of its future wants, she then compounds a
delicate mass of pink conserve, which she collects from thistles, and
subsequently stops up each cell with thin pieces of leaf, as exactly
round as if they had been cut out with a punch, or by means of some
mathematical instrument.

Réaumur says he often, in the month of May, on looking at his
rose-trees, detected these insects at their work; all he had to do
was, to stand and patiently watch by the side of a tree, the leaves
of which exhibited the singular marks made by this insect. Many times
have the same appearances arrested our attention, and without doubt
that of the reader. The spectacle of insect ingenuity which it affords
well promises to repay a little exertion in endeavouring to find out
the nest to which the pieces are conveyed, and some neighbouring post
or footpath will probably discover it to us after a sharp scrutiny.
Sometimes the insect makes a bad choice of a leaf; it may be, perhaps,
too tough for her; but she soon discovers her mistake, and leaves it,
half cut, to seek a better on the same branch.

[Illustration: _A Rose-branch cut by the Bee._]

The nest formed by a species of moth for depositing her eggs in, is one
equally interesting to describe. From the resemblance of her actions
to the well-known account of those of the eider-duck, whose maternal
love strips her breast of down for the purpose of protecting her eggs,
we might almost venture to call this moth the eider-moth, were it not
that it is known under another and far less appropriate name--the
gipsy-moth. Indeed, in the care of the insect the mother's love is,
as we might say, even more powerful than in the bird; for, while the
latter has the pride and pleasure of seeing her little ones grow up
around her, the poor insect, after stripping herself of her own soft,
warm down, thus testifying her love to her offspring even to death,
presently expires. The insect in forming her nest first plucks off, by
means of a singular instrument, like a pair of tweezers, with which
she is provided, a little portion of down from her body; seated upon a
tree, she attaches this to its trunk, and then deposits an egg in it,
which immediately adheres to the down, and becomes coated with it. The
remainder of her operations, until she has deposited the entire number
of eggs, are but repetitions of the same actions. When the process is
at an end, she begins to form a regular tile or covering to her nest,
and this she effects with a degree of skill not unworthy of the most
consummate thatcher. She arranges the hairs of the down just as the
thatcher does his stems of straw for the cottage roof, so that they
all slope downwards, resembling much the smooth pile of a hat. By this
arrangement of the down, it is next to impossible that in the most
drenching shower the eggs, warmly wrapped up within, should be wetted
or otherwise injured, and the down itself, being a material which, as
we all know, is a non-conductor, preserves the eggs from the influence
of the most severe frosts. In shape, this nest of eggs resembles a
skittle, or a truncated cone, the broad end downwards. The engraving
represents this form, and also shows the insect at work constructing
the nest.

[Illustration: _The Nest of the Gipsy-moth._]

[Illustration: _Eggs of Lackey-moth._ (_Natural size, and magnified._)]

Let us now pass on, to mention, that many eggs are deposited without
any special protection of the kind we have described, and without what
would be with propriety termed a nest. A moth, called the lackey-moth,
frequently ornaments the young twigs of trees in our gardens with
exquisite bracelets of glistening white eggs, looking like beads. From
two to three hundred of these eggs are glued on by the insect around
the twig, by means of a tenacious waterproof cement, and are arranged
with an accuracy of the most marvellous character, in a close spiral
line upon the twig. The cement employed by the insect in uniting her
eggs, and in varnishing them over, is so hard as to serve the purpose
of a covering, which admirably casts off the rain, and preserves the
eggs free from injury by the elements all the winter long. Many eggs
are simply glued on irregularly upon the stems and leaves of plants,
their shells or outer coating, together with the protecting varnish,
being sufficient to preserve them from the inclemencies of the weather;
but some are piled together with the most striking regularity, in
regular columns of eggs.

In addition to these, it is proper to state, that some insects lay
their eggs in the body of the young of others. Of these, those which
are most dreaded by the insect tribe are the little but terrible flies,
called Ichneumons. They are so called because in their actions they
agree with the popular account of those of the ichneumons of Egypt,
which were venerated as the destroyers of the eggs of serpents and
crocodiles. "Such," say Messrs. Kirby and Spence, "is the activity
and address of the ichneumons, that scarcely any concealment, except
perhaps the waters, can secure their prey from them; and neither bulk,
courage, nor ferocity, avail to terrify them from effecting their
purpose. They attack the ruthless spider in his toils; they discover
the retreat of the little bee, that for safety bores deep into timber;
and though its enemy, the ichneumon, cannot enter its cell, by means
of her long ovipositor (organ for depositing the egg), she reaches the
helpless grub, which its parent vainly thought secured from every foe,
and deposits in it an egg, which produces a larva that destroys it. In
vain does the destructive _cecidomia_ of the wheat conceal its larvæ
within the glumes that so closely cover the grain; three species of
these minute benefactors of our race, sent in mercy by Heaven, know
how to introduce their eggs into them, thus preventing the mischief
they would otherwise occasion, and saving mankind from the horrors of
famine. In vain, also, the _cynips_, by its magic touch, produces the
curious excrescences on various trees and plants, called gulls, for the
nutriment and defence of its progeny. This parasite insect discovers
its secret chamber, pierces its wall, however thick, and commits the
destroying egg to its offspring." In vain, also, might we add, does
the sand-wasp excavate her deep cell for her young ones; for when once
the ichneumon has discovered the retreat, the destruction of the young
larvæ is inevitable. She pierces through the defences piled over the
mouth of the cavity, with all the precision and patience of a higher
creature, and rests not until she has thrust down her long ovipositor,
and placed the egg in the body of the helpless prisoner below, when she
flies away, confident that the days of her victim are numbered, and
having thus doomed him to be eaten up alive! The common caterpillar,
which, by its ravages in our cabbage rows, makes itself a little too
familiar to us, has a fierce enemy in these flies; they dart upon it,
pierce its body in many places, laying an egg in each wound; these
in due time become hatched, and eat their way out of the body of the
poor caterpillar, who soon dies, while the larvæ, after undergoing
their proper transformations, become perfect insects themselves, fully
equipped to proceed to the same work in some other individual of the
caterpillar kind.

To man, this ordinance of the Creator, that some insects should lay
their eggs in the bodies of others, and so destroy them, is of
inestimable benefit. It is quite impossible to imagine what would be
the result, were weevils, caterpillars, and such like insects, to be
permitted to multiply without a check. Produce of all kinds would soon
be consumed, and the desolations of an universal famine would overwhelm
man and beast. But God has been pleased to ordain it otherwise. In
proportion to the increase of the destroyers is the increase of those
that prey upon and destroy them. Thus, what has been well called the
balance of creation is preserved, and by means of the insects in
question, conjoined to other causes, is the command to the destroying
powers enforced--"Hitherto shall ye come, but no farther."




CHAPTER II.

STRUCTURE AND CONTENTS OF THE EGG.


In the past pages we have now considered shortly the various methods of
depositing the eggs of insects, and have seen that the nursing place
where the young being is produced, differs widely both in point of its
position, and of the external circumstances which variously affect
it. For some are the deep-bored galleries in timber; for some, the
hard-wrought tunnel, scooped by an insect out of a rock; for some, the
ingeniously-formed boat or raft, which is to carry its cargo of life
buoyant on the dancing waters "all the days of its appointed time,
waiting until its change come;" for some, the cell of earth lined with
painted hangings, exquisite in make and colour; for some, the little
leaf-case, curiously folded together; but for others, none of those
works of insect art are provided; they, hid in a rain-proof covering of
varnish, lie open to every eye, or scattered here and there on all and
every kind of flower and herbage, lie at the mercy of every wandering
foot. While, lastly, others are buried with a cruel yet merciful
art, in the bodies of myriads of unsuspecting members of the insect
community, lying, like the seeds of evil in the heart of the infant,
dormant awhile, but destined to grow with its growth and to strengthen
with its strength.

The time has, therefore, now come that we should speak a little more
particularly upon the nature and character of the eggs of insects. The
shape of an insect's egg, although frequently something of an oval in
its outline, is very various; in fact, were the egg of some peculiar
species placed in the field of a microscope, probably not one general
observer out of a hundred could in the least imagine what the object at
which he was looking really was. Sometimes they are oval and exactly
resemble the form of the egg of the bird; but in other instances they
are of the most irregular and fantastic appearance. Some look like
pill-boxes tied over and down their sides with string; others look like
tiny flasks, with many raised ribs upon their surface; others have lids
and springs. The gnat's egg resembles a chemist's phial, or one of the
new bottles for holding aërated waters; and those of the dung-fly have
two little pieces sticking out at the top on each side to prevent them
sinking too deep into the matter upon which they are deposited.

[Illustration: _Various forms of Eggs._]

[Illustration: _Eggs of Lace-winged Fly._]

The eggs of some insects strikingly resemble the little shells like
turbans with which we are most of us familiar. A very singular variety
of egg which has often caused much perplexity to naturalists is the
egg of the lace-winged fly. Réaumer says, "I had observed them several
years without actually knowing what they were. Others as well as myself
had noticed that on the leaves and twigs of many trees were a number
of minute stalks placed together, scarcely as thick as a hair, their
colour was nearly white, and they were about an inch in length; there
were sometimes ten or twelve placed in a bunch; the end of each stalk
bore a small head of an egg-like or oblong figure. They appeared to me
to be fungi, the little head precisely resembling the appearance of
moulds as seen under the microscope; but they were larger in size."
They were, in fact, the eggs of the fly in question. When the larva
escapes from them they have much the appearance of little vases; and
the same author assures us that they were once described and engraved
by a naturalist as some curious minute flower growing on the leaves of
the elder, for which he was unable to account. The representation of
them in the cut will enable the reader to form his own opinion as to
the difficulty of ascertaining whether they were flowers or the nests
of an insect.

[Illustration: _Manner of depositing the Egg._]

The manner in which these eggs are thus regularly placed by the
insect is interesting. Placing herself upon the leaf in the attitude
represented, she fastens a thread to the leaf, draws it out in the same
way as a spider does her lines, and when it has got sufficiently firm
the wise insect then puts forth the egg, glueing it to the extremity
of the stalk; this done, she quits it and begins to form another,
repeating the same actions until the proper number is laid. Poised on
the summit of these slender pillars the eggs are secure from every
invader but man himself, and in time there comes from them the larva
which is to become the beautiful insect, the "lace-winged fly," in all
the elegance of its form.

From what has been already stated, the surface of the eggs of insects,
it will be perceived, is by no means in all cases smooth and polished
as in the case of birds. Far otherwise. To look at some of them by the
help of a magnifying glass we should imagine that they were covered
with very fine lace net, others appear as if some clever engraver had
been chasing some intricate design upon their surface. The eggs of a
species of butterfly are studded over with an infinite number of little
knots or tubercles; and those of another are capped at the top with
sculptured work disposed in the form of a circular tiling or roof to
the egg. Some also closely resemble embossed buttons.

He who has thus adorned these minute objects with beauty of form
and carving, has likewise bestowed upon them the most beautiful and
variegated colours--colours such as no human art can imitate. But from
the small size of the eggs it is difficult to appreciate this beauty
in them except when they occur in a mass. The most common tints are
white, yellow, and green, but the richer and rarer hues are also to
be found among them. Thus, the eggs of a moth are of a beautiful blue
colour, banded in the most delicate manner by three zones or rings of
brown, the contrast being very pleasing. Another moth, which loves
to deposit its eggs in the bark of the willow, produces them tinged
with a purple more delicate than ever Tyrian lady wore as the finest
produce of the dyer's art. In the deep crevices of the bark of the elm,
and only, therefore, to be found by sharp scrutiny, another moth lays
eggs of a lovely pink. Messrs. Kirby and Spence write, "We remember
once being much surprised at seeing the water at one end of a canal
in our garden as red as blood; upon examining it further we found it
discoloured by an infinite number of minute red eggs." Sometimes eggs
are spotted, and thus resemble the eggs of many birds; and, strange to
say, sometimes they change colour in a very remarkable manner; so that,
as far as colour is concerned, an observer could scarcely believe that
the egg was the same he beheld, perhaps, a few days previously. The
eggs of the chameleon fly, as we are told by the gentlemen last quoted,
are at first pure white; then change to green, and finally turn to a
deep olive-green. Others are at first mouse-coloured, then reddish,
and, lastly, black. The eggs of a kind of moth we have seen first of
the colour of sulphur, then becoming _green_, after that _rose-colour_,
and lastly, _black_. In the instances of the common gnat and silk-worm,
similar changes of colour take place. The eggs of the gnat are first
white, then green, and finally gray; and those of the silk-worm are in
the first instance of a pale yellow, and ultimately take on a violet
tint.

Having thus noticed these points in connexion with the Life of an
Insect, we are led to that most important of all periods, the dawn
of life in the egg, or, in common terms, the period of hatching. But
before proceeding to the subject, may we not pause and wonder as we
behold the varied manifestations of the Creator's wisdom in the actions
of the minute, and, as we often call them, insignificant creatures of
whom we have spoken? Should David say, when he beheld the sun, moon,
and stars, as the work of a Divine hand, "Lord, what is man, that thou
considerest him, or the son of man, that thou regardest him!" And
shall not we, as we contemplate the few particulars here set down of
the wonders of insect-life, exclaim, with even greater astonishment,
"What are these, that thou considerest _them_?" Let no one then say,
that entomology, or any other natural science whose field of study lies
chiefly among the minute portions of creation, are profitless sciences,
when they can reveal to us such a display of the power, wisdom, and
love of God, as is exhibited even in this small portion of the Life of
an Insect.

Let us then take up one of these eggs, so minute, but containing within
it the rudiments of a being which is in time to assume a form of
considerable magnitude, by comparison, and to be adorned with colours
richer than art can boast of, and let us examine it on the field of a
tolerably powerful microscope. We need not look far for a specimen. In
the dark corner of the ceiling in a neglected room, after removing the
mass of dust-filled webs that have accumulated there for months, we may
find without difficulty a spider's nest of eggs. A more pleasant place
to search for insects' eggs is, perhaps, the garden; and if in the
crevices of the bark of the trees, or attached to twigs or branches,
none can be found, we can almost certainly promise success if the
reader will carefully and patiently search the angles of the garden
walls, particularly if he has noticed in the preceding autumn many
of the beautiful webs of the garden-spider. There, in some sheltered
recess, where the pattering rain-drops may be heard, but never venture
in, and where few eyes would detect them, may be found little round
yellow balls, of the size of a small cherry, made of the most beautiful
golden-coloured silk, and attached by a slender stalk to the wall, or
perhaps, to a twig. Sometimes they exhibit the more elegant and curious
appearance shown in the figure on the next page, resembling an inverted
wine-glass or pear.

[Illustration: _Nests of Garden-Spider._]

On taking our prize in-doors, by the aid of a very sharp penknife
we may succeed in cutting it smoothly open, and in turning out some
of the delicate eggs which lie warmly covered up at the bottom.
Taking one of them up on the point of the knife, and laying it on the
microscope-field, we shall be able to see something of the anatomy of
an insect's egg.

First, we may notice what seems to be the shell; that is, the outer
covering of the egg. This is very different to the hard, calcareous
eggshell of birds. It is stated not to contain any lime in its
composition as the shells of birds do; for when the eggs of insects are
put into very weak sulphuric acid and water, which would act on the
lime if it were present in their composition, they are not affected by
it. Although, therefore some eggs of insects are very hard: so hard
indeed as to resist severe pressure with the nail, they do not owe
their hardness, as do the eggs of birds, to any lime in their chemical
composition. The outer coat or shell is apparently simply membraneous,
frequently varying greatly in thickness, being sometimes as dense and
horny as we have mentioned, and at others, so delicate as to burst with
the gentlest touch.

[Illustration: _Nests of Spiders._]

Could we now do, what it is so easy to do with the egg of a
fowl,--carefully take off a little portion of this outer shell, we
should be able to inspect its contents more accurately. But in the case
of most who read this book, this extremely delicate task will prove
after many trials probably a hopeless failure. Let us state, therefore,
what some expert and talented observers have found within the insect's
egg. It appears, then, that although there is both a "yolk" and a
"white" in the tiny egg before us, that they are not quite so distinct
as in the bird. Yet, they are sufficiently separate from one another
to make their differences complete. Probably the reader has noticed in
the hen's egg a little round spot in the middle of the "yolk" or yellow
portion; from this the future bird is produced. Although from their
extreme minuteness it is difficult to detect anything of this kind in
the eggs of insects, some observers state they have seen a similar
little spot in them also. Thus, M. Herold says, that in the eggs of the
very insect whose nest we have robbed, the garden spider, "this little
spot can be seen as a minute white point immediately under the shell,
and in the middle of its circumference." This was seen by holding it
up to the light, and the spot was more carefully examined by gently
pressing the contents of a spider's egg upon a watch-glass. Mr. Rennie
says, that "the point where the caterpillar originates, answering to
the scar in the eggs of birds, we can readily distinguish even by the
naked eye in the larger species of eggs, as it lies always immediately
under the shell." But it may be doubted whether, without the assistance
of some one versed in entomology, many who make the same attempt,
will succeed. So much depends in looking at any object upon whether
we know what to look for or not, so that things which are as clearly
seen as possible by the eyes of the initiated, are not seen at all by
any others. To perceive some things in natural history, and many in
science, the senses of sight, hearing, and touch, require to be well
educated, and they then become apparent enough.

And is this all that we can mention about the structure of an egg?
This indeed is all. Can it be possible? Is there no striking and
broad difference to mark the nature of the future insect? Is the egg
of a spider the same in the number and nature of its parts as that
of a butterfly, or the egg of a gnat as that of a beetle? Surely, as
we should imagine, there must be some important differences between
these, otherwise why such immense differences in the perfect insect?
Could any one imagine that a grasshopper and a house-fly, so strangely
unlike each other in their perfect forms, originated in eggs to either
of which the same description of an insect's egg would accurately
answer, and leave nothing out? However great our amazement, the fact
is unquestionable. The egg of every insect at first consists of an
outer covering, a white, a yolk, and the little spot we have alluded
to. We might have thought that in creating so many different species of
insects, which differ so surprisingly in form as the insect tribes do,
the great Creator would have formed their eggs essentially different
too. But, except in the matter of shape, all are originally alike;
and the wisest philosopher is unable to inform us of any essential
difference in the eggs of insects at first. The eye of God, who knows
the end from the beginning, sees some difference inappreciable to the
eye of man. He said to this kind, "Be thou thus," and to that, "Be thou
different;" but until the time comes when the young insect is much more
advanced, it is not possible for us to recognise those marks of variety
which His hand has laid upon them from the beginning.




CHAPTER III.

LIFE BEGINS IN THE EGG.


The eggs of birds are, in most instances, hatched by the warmth of the
mother, who sits for a certain time covering them with her wings and
downy breast. But the exception to the rule in insects is that the
mother has anything to do with rearing her young brood; the cases in
which this takes place will be noticed in our next chapter. Generally
speaking, the eggs of insects are hatched by the increasing temperature
of the air in spring. The following sketch, extracted from Mr. Darwin's
interesting Journal of the Voyage of the Beagle, sets before us, in
a very pleasing manner, the awakening influence of this season to
all nature:--"When we first arrived at Bahia Blanca, September 7th,
1832, we thought nature had granted scarcely a living creature to this
dry and sandy country. By digging, however, in the ground, several
insects, large spiders, and lizards, were found, in a half-torpid
state. On the 15th a few animals began to appear, and, by the 18th,
(three days from the equinox,) everything announced the commencement
of spring; the plains were ornamented by the flowers of a pink
wood-sorrel, wild peas, _oenotheræ_, and geraniums; and the birds
began to lay their eggs. Numerous beetles were crawling about, while
the saurian tribe, the constant inhabitants of a sandy soil, darted in
every direction."

As to the torpid animal and buried seed, so to the carefully laid up
egg, the returning warmth of the air is the signal for the commencement
of life. The winter-clouds roll reluctantly back, as the genial days of
spring advance, and the changes which are to have their accomplishment
in the production of a living being out of the minute object before
us, are set in movement as the days grow bright and pleasant. That the
hatching of the egg, in most cases, is due chiefly to the stimulating
influence of heat, is now well ascertained. The school-boy who has ever
amused himself with silk-worms can well assure us of this fact, for he
is in the habit of hatching the insect's eggs by carefully wrapping
them in paper, and keeping them in his waistcoat-pocket, where they
have all the comfort and warmth of his body to bring them forward. In
countries where the silk-worm is reared, women carry them in their
bosom, and by this means cause the young larva to come forth from the
egg in much less time than it would naturally occupy. By removing a
twig of a plant upon which in the preceding autumn an insect may have
been found to have deposited its eggs, into a warm room, an opportunity
will be had of putting this operation practically to the test. In a
short time it will be found that the eggs are all hatched, and that
a number of minute larvæ are crawling actively about, while their
brethren in the snow-covered fields are yet safely asleep in the shell.

On the other hand, eggs which would otherwise be hatched the same
year are arrested by the advancing cold of the winter season, and are
now compelled to wait until the ensuing spring, before their time of
hatching arrives. Evidently, therefore, to the commencement of the
life of an insect the condition of the external temperature is an
all-important consideration. Before proceeding immediately to consider
the nature of the changes, it may be mentioned as an interesting fact,
that although the eggs of insects are very quickly sensible of a slight
increase of heat, and in consequence of its application to them very
soon begin to live, yet they will endure the most severe degrees of
cold almost without injury. As an illustration of this point we may
transcribe a few sentences from a paper by the great Spallanzani upon
this subject:--

"The year 1709, when the thermometer fell to 1° Fahrenheit," or
thirty-one degrees below freezing point, "is celebrated for its rigour
and its fatal effects on plants and animals. 'Who can believe,'
exclaims Boerhaave, 'that the severity of this winter did not destroy
the eggs of insects, especially those exposed to its influence in the
open fields, on the naked earth, or on the branches of trees? Yet, when
the spring had tempered the air, these eggs produced as they usually
did after the mildest winters.'" He adds further on, "I have exposed
eggs to a more rigorous trial than the winter of 1709--those of several
insects, and among others the silk-worm, moth, and elm-butterfly, were
enclosed in a glass vessel, and buried five hours in a mixture of ice
and rock-salt, the thermometer falling 6° below zero. In the middle of
the following spring, however, caterpillars came from all the eggs,
and at the same time as from those which had suffered no cold. In the
following year, I submitted them to an experiment still more hazardous.
A mixture of ice and rock-salt, with the burning spirit of nitre,
reduced the thermometer 22° below zero, that is, 23° lower than the
cold of 1709, or 52° lower than the point at which water freezes. They
were not injured, as I had evident proof--by their being hatched."

When it is known that many seeds will not endure these degrees of cold
without injury, and those even of some tolerably hardy plants, it
is the more surprising to find such apparently delicate and readily
damaged objects as the eggs of these members of the insect tribe thus
resisting an intensity of cold to which, in a state of nature, they
are scarcely ever exposed. It is impossible to assign any rational
explanation of these singular facts. It is undoubtedly owing to this
power of resisting the generally deadly influence of extreme cold
that we find insects reappear in spring, even in countries where the
winter is much prolonged, and is of extreme severity. Thus, in Lapland
we should have probably thought that the rigour of the climate would
have been fatal to all insects in winter, in any condition, whether
in the egg, or in other forms; but, as the poor inhabitants know to
their cost, it is far different. The mosquitoes swarm in that country
in numbers so prodigious that they have been compared to a fall of
snow, or to the dust of the earth. The wretched natives cannot take a
mouthful of food, or lie down to sleep in their cabins, unless they
are fumigated to a degree almost dangerous to life. They fill the
mouth and nostrils, and, minute though they are, render existence
almost a burden by their blood-thirsty propensities. Not even thick
plasters of the most offensive compounds,--tar, oil, and grease, are
sufficient to shield the Laplander's skin from their attacks. The
great John Hunter considered that this power of resisting cold was,
in some unexplained manner, connected with the existence of a living
principle in the egg, which had the effect of withstanding a degree
of cold that would otherwise have been fatal to it; but, after all,
this is only an apology for an explanation. When we are unable to
clear up the difficulties of a natural history question like this,
although we cannot explain, we are not prohibited from admiring, and
can clearly perceive, that in thus endowing the eggs of insects with a
self-preservative power, God has manifested his wisdom and forethought;
for had it been otherwise, the lapse of a few seasons would have
depopulated the insect world, leaving us, it is true, without a gnat
or a mosquito to annoy us, but also without a silk-worm, or a bee, to
supply us with the precious products of insect industry.

The frosts have disappeared, the air brightens, the sun loses its pale
aspect, and glows with a more golden face. The days lengthen, the
breeze has lost its penetrating chilliness, gentle showers descend
and water the earth, and there is a general voice heard all over
creation,--"Spring has come!" The eggs of a thousand insect species
have already perceived its presence, and the newly-awakened beings
within hasten to welcome it by bursting from the shell, their long
occupied, but now for ever forsaken dwelling-place. Sometimes the young
larva bursts through the thin walls of the shell by main force, or eats
its way through by means of its jaws, which is occasionally a task of
many hours' duration. "In many instances, however," write Messrs. Kirby
and Spence, "the larva is spared this trouble, one end of the egg being
furnished with a little lid, or trap-door, which it has but to force
up, and it can then emerge at pleasure. Such lids are to be found in
the eggs of several butterflies and moths. The eggs of a species of
bug, besides a convex lid, are furnished with a very curious machine,
as it would seem, for throwing it off. This machine is dark brown, of
a horny substance, and of the shape of a crossbow; the bow-part being
attached to the lid, or pushing against it, and the handle, by means of
a membrane, to the upper end of the side of the egg."

But if, in our account of the various attendants on the opening of
spring, we had mentioned every circumstance that takes place at that
time, alas! for any poor insects, or, at least, for a large number
of them, who should be hatched at that time. The warm air and gentle
shower, and brighter sky, would ill satisfy them in the absence of all
_food_, and they would be born, by a cruel destiny, only to starve and
die. We well know this is not the case; but there are, probably, few
persons who have ever thought much upon the admirable arrangement by
which the occurrence of such a calamity to many of the insect tribes
is avoided. We need scarcely remind the reader that in the opening
sentence of the last paragraph there is one most important omission in
the sketch of the phenomena of returning spring; that is, that there
is no mention of what takes place in _plants_,--of the putting forth
of their young and tender leaves. Now, as a majority of insects in the
larva state are vegetable-feeders, we can easily understand that the
unfortunate little beings if hatched before the appearance of leaves
would, without doubt, quickly perish for lack of proper food. Yet the
returning warmth of the air is all that is requisite to call the insect
into existence, and if by the time it is ready to burst from the shell
there is not food all prepared for it, it must die. The difficulty has
been beautifully provided for; and perhaps, few other instances of
the wisdom of the Creator in forming the insect world are so full of
instructive thought as this. It has been ordained, then, that soon as
winter is over, the plant is _first_ to obey the voice of spring, and
to awake; and the bursting buds on its lower boughs are already full
charged with sap long before the young insect being that is to be fed
therewith has left the shelter of the egg.

One of the talented authors of the Introduction to Entomology relates
a pleasing anecdote in reference to this simple, yet admirable
arrangement, and mutual adjustment of these two events,--the awakening
of life in the plant and in the insect. "On the 20th of February, 1816,
observing the twigs of the birches in the Hull Botanic Garden to be
thickly set, especially about the buds, with minute oval black eggs
of some insect with which I was unacquainted, I brought home a small
branch, and set it in my study, in which is a fire daily, to watch
their exclusion. On the 28th of March I observed that a numerous brood
of _aphides_ had been hatched from them, and that two or three of the
lower buds had expanded into leaves, upon the sap of which they were
greedily feasting. This was full a month before either a leaf of the
birch appeared, or the egg of an _aphis_ was disclosed in the open
air." Thus showing that the coming to life of the branch and of the
insects resting on it, was beautifully arranged to take place each at
the proper time.

It is very singular to add, that as some trees acquire their leaves
earlier or later than others, the eggs of insects which are deposited
on them, never are hatched before the leaves appear, even while some
of their companion eggs of a different species, and placed, therefore,
on different trees, may have long since sent their young into the
world. Thus, we learn that not only has God been pleased to arrange
_generally_ the hatching of the eggs of insects, and the putting
forth of the leaves of trees, so that the latter shall precede the
former, but it has also been ordered that the eggs deposited on each
_particular_ plant shall be hatched just when the time of that plant's
putting forth its leaves shall arrive, at whatever period that may be.
This may be more readily comprehended by an example: thus, there is no
difference, so far as we can perceive, between the eggs of the little
insects just mentioned as feasting on the leaves of the birch, and
those whose food is the leaf of the ash; yet the birch will be in leaf
nearly a month before the ash-tree, and the eggs deposited on it will
therefore be hatched a month before those placed upon the ash, although
both trees are in the same position with regard to warmth, and may
even, perhaps, be within a yard or two of one another. What a beautiful
and mysterious link is this, between events so disproportionately
important as the clothing of a great tree with its leafy garments and
the coming to life of a little throng of beings, whose dwelling-place
is a small twig, and whose world a green leaf! Yet it was not too
insignificant a matter for Him to arrange whose dwelling-place is
eternity, and who takes up the islands as a very little thing. Does God
take thought for these, and will He not much more care for and arrange
well every event in the lives of his faithful children? Surely, yes.

Speaking generally, the time taken up in hatching the eggs of insects
is very variable. It is a general rule that the eggs which are laid in
the autumn must abide the return of spring before they will be hatched.
But when eggs are deposited in the summer, they are often hatched in a
very short time. The eggs of the painted-lady butterfly are hatched in
about eight days, those of the lady-bird in a little less, from five
to six days; the eggs of another species of butterfly occupy a month,
those of spiders three weeks, those of bees only three days, and those
of the meat-fly shorter than any--only a few hours; it has even been
stated that in very warm weather the eggs of the meat-fly will be
hatched in about two hours! In most of these cases much depends upon
the weather; but even this does not operate beyond certain limits, for
it has been said that in the month of June, even if silk-worm's eggs
were placed in an ice-house, they would be hatched in spite of the
cold, but this observation deserves to be repeated.

It would be impossible to make the exact nature of the changes which
take place in the egg from first to last easily understood in a work of
this kind. They have occupied the laborious investigation of talented
observers with the highest powers of the microscope, and although
much is now known on the subject, it is of a nature too abstruse to
be dwelt upon in our unpretending volume. As we may well imagine,
the changes are wonderful indeed which from a little drop of fluid
matter, contained perhaps in a shell not larger than a pin's head,
end in the development of the living and active larva, who makes his
speedy escape out of his shell-cradle. But they must be studied in the
scientific treatises which are written upon this subject, and they are
so interesting as amply to repay the task of investigation. It may be
added, however, as a curious fact, that contrary to the general rule
in the egg of birds, some of the eggs of insects actually grow larger
before they are hatched, and frequently the shape alters also.

In our account of the nests made by insects for their eggs, the
examples quoted, although they furnished us with many proofs of a
mother's care and forethought on the part of the insect, yet there was
no instance given of anything like the solicitude displayed by the
hen over her eggs. Are there then no anxious mothers concerned in the
well-being of their eggs among insects also? In the next chapter some
instances of a mother's care over the young larvæ will be given; and
before we conclude the present, mention may be made of some interesting
observations upon this subject made by the eminent naturalist M.
Bonnet. The insect upon which his observations were made was the
spider, so commonly found on turning up a log of wood in the fields,
or a clod of earth. She carries her eggs about with her in a little
round white pouch of silk attached to her body. Well has it been said,
"Never miser clung to his treasure with more tenacious solicitude than
this spider to her bag. Though apparently a considerable incumbrance,
she carries it with her everywhere." M. Bonnet found that he could not
beat away the affectionate creature from her treasure, and on forcibly
removing it from her she instantly lost her ferocious aspect and became
tame. In this emergency she stops to look around her, and begins to
walk at a slow pace, and searches diligently on every side for her lost
eggs, nor will she fly if threatened by the bystander. If, however, out
of compassion, the bag is restored to her, she darts forward, catches
it up with all the intensity of a mother's love, and runs away with it
as fast as possible to some secret place where she may again have the
opportunity of attaching it to her body. In order to put this insect's
affection for her eggs to a test, M. Bonnet threw a spider with her
bag into the den of a ferocious insect, called an ant-lion, who lurks
at the bottom, like the Giant in the "Pilgrim's Progress," waiting for
poor insect-travellers to drop into the pit which it forms, and then,
rushing out, devours them. "The spider endeavoured to escape, and was
eagerly remounting the side of the pit, when I again tumbled her to
the bottom, and the ant-lion, more nimble than the first time, seized
the bag of eggs with his jaws, and attempted to drag it under the sand.
The spider, on the other hand, made the most strenuous efforts to
keep her hold, and struggled hard to defeat the aim of the concealed
depredator; but the gum which fastened her bag not being calculated
to withstand such violence, at length gave way, and the ant-lion was
about to carry off the prize in triumph. The spider, however, instantly
regained it with her jaws, and redoubled her efforts to snatch the bag
from the enemy; but her efforts were vain, for the ant-lion being the
stronger, succeeded in dragging it under the sand. The unfortunate
mother, now robbed of her eggs, might at least have saved her own life,
as she could easily have escaped out of the pitfall; but wonderful
to tell, she chose rather to be buried alive along with her eggs. As
the sand concealed from my view what was passing below, I laid hold
of the spider, leaving the bag in the power of the ant-lion. But the
affectionate mother, deprived of her bag, would not quit the spot where
she had lost it, though I repeatedly pushed her with a twig. Life
itself seemed to have become a burden to her since all her hopes and
pleasures were gone for ever."

As this spider may be easily found in the localities we have mentioned,
it may interest some of our readers to make trial of the mother's care
for her eggs; but, let us hope, only in a gentle spirit. Never let us
be guilty of the cruelty above narrated, and leave the disconsolate
mother, after her hard struggle for her treasure, without restoring
it back to her. Even in an insect, a mother's love, so faithful,
self-devoted, and constant, is a sacred thing; and while, as an
illustration of the care it has pleased the Creator to implant in it
for its offspring, it may be lawful to put it to the trial, it is wrong
and cruel to do more. Never let us, for our own amusement, give even to
an insect that depth of anguish and despair so beautifully expressed in
the words of Jacob, as translated in the margin of our Bibles: "And I,
as I am bereaved of my children,--I am bereaved."

"In order to prove," says the author of Insect Architecture, "whether a
spider of this species could distinguish her own egg-bag from that of
a stranger, we interchanged the bags of two individuals which we had
put under inverted wine-glasses; but both manifested great uneasiness,
and would not touch the strange bags. We then introduced one of the
mothers into the glass containing her own eggs and the other spider;
but even then she did not take to them, which we attributed to the
presence of the other, as all spiders nourish mutual enmity. Upon
removing the stranger, however, she showed the same indifference to her
eggs as before, and we concluded that, after having lost sight of them
for a short time, she was no longer able to recognise them."

The common earwig, a name at which some, who little know the beautiful
traits in her character, are apt to shudder, still more closely
resembles the affection of a higher animal than does the spider just
mentioned. The following most interesting notice of her proceedings
was published by a writer[B] in the _Penny Magazine_ some time since.
He says: "About the end of March I found an earwig brooding over her
eggs in a small cell scooped out in a garden border; and in order to
observe her proceedings, I removed the eggs into my study, placing
them upon fresh earth under a bell glass. The careful mother soon
scooped out a fresh cell, and collected the scattered eggs with great
care to the little nest, placing herself over them--not so much, as it
afterwards appeared, to keep them warm, as to prevent the too rapid
evaporation of their moisture. When the earth began to dry up, she
dug the cell gradually deeper, till at length she got almost out of
view; and whenever the interior became too dry, she withdrew the eggs
from the cell altogether, and placed them round the rim of the glass,
where some of the evaporated moisture had condensed. Upon observing
this, I dropped some water into the abandoned cell, and the mother
soon afterwards replaced her eggs there. When the water which had been
dropped had nearly evaporated, I moistened the outside of the earth
opposite the bottom of the cell, and the mother, perceiving this,
actually dug a gallery right through to the spot where she found the
best supply of moisture. Having neglected to moisten the earth for
some days, it again became dry, and there was none even round the rim
of the glass as before. Under these circumstances, the mother earwig
found a little remaining moisture quite under the clod of earth, upon
the board of the mantel-piece, and thither she forthwith carried her
eggs. The subsequent proceedings were not less interesting; for though
I carefully moistened the earth every day, she regularly changed the
situation of the eggs morning and evening, placing them in the original
cell at night, and on the board under the clod during the day, as if
she understood the evaporation to be so great when the sun was up, that
her eggs might be left dry before night. I regret to add, that during
my absence the glass had been removed and the mother escaped, having
carried away all her eggs but one or two, which soon shrivelled up."

Our diligent little exemplars, the ants, are equally careful about
their eggs. So soon as they are produced, the ants catch them up and
convey them to a separate chamber, moistening them with their tongues,
and incessantly turning them backwards and forwards. They are the
objects of constant solicitude until they are hatched; they are carried
hither and thither according as the temperature of the nest varies.
On a sunny morning they are brought out and laid to bask in the warm
air; but if the sky becomes overcast, and heavy clouds threaten rain,
the careful nurses whip up the eggs and hasten with them down to the
deepest recesses of the nest. They even appear to imitate the brooding
of the hen, and sit upon the eggs to impart to them some of the warmth
of their own bodies.

Before concluding this chapter, and entering upon the more striking
manifestation of life in the form of the insect which will next
come under our observation, it will be useful just to allude to the
comparative number of eggs which some insects produce, which we shall
place in the form of a table:--

  The Noon-day Fly             2
  The Flea                    12
  May Flies                  100
  Silk-worm Moth             500
  Other Moths       1000 to 1600
  Wasps                   40,000
  Bees                    50,000

The most enormous number of all is produced by the queen of the white
warrior ants. She deposits sixty eggs every minute, which is at the
rate of 31,557,600 eggs in the course of a year, if we allow that she
goes on laying at the same rate constantly, which is, perhaps, scarcely
correct.

Were all the eggs produced by insects to be hatched and to bring
forth living progeny, we may well ask what would become of mankind?
Unquestionably in a short time their numbers would multiply so
excessively as to sweep every green thing off the face of the earth,
and man and beast would experience all the horrors of famine. But they
are the sport of a thousand accidents, which destroy them and keep down
the threatened excess of population in this world of busy creatures.
And when the young larva has been put forth, this check upon their
tendency to over multiplication is still more prominently displayed, as
we may presently have occasion to remark.

[Illustration: FEROCIOUS LARVÆ OF DRAGON-FLY.

Page 120.]




PART II.--THE LARVA.




CHAPTER I.

THE YOUNG LARVA.


The generality of insects, as has been before mentioned, are destined
never to behold the birth of their progeny, nor to experience either
the pleasures or the cares of parents surrounded by their families.
Their anxieties cease when they have carefully stored up their eggs,
and their existence is generally soon afterwards at an end. The insect
world, therefore, presents us with but few opportunities of witnessing
the display of a parental affection on the part of its members; but,
as was mentioned in the conclusion of the last chapter, a few examples
of the kind do exist, and, perhaps, the very fact of their being few
in number contributes to make them the more interesting to us. We have
seen a noble instance of self-devotion on the part of a poor spider
in defence of her eggs. Let us now turn to some examples of the love
of an insect mother for her young larva. If the reader will carefully
search the twigs and leaves of the birch-tree in the month of July he
may possibly succeed in finding the little insect, the field-bug, of
which mention is about being made, and witness for himself the strange
spectacle described in the following account from the great work on
insects by De Geer. In order that it may be recognised, we have here
adjoined a representation of the insect. Its colour is a greenish gray
on the back, dotted all over with very minute black spots; the under
portion of the insect is greenish yellow, with black spots. It lives
upon the sap of the birch-tree.

[Illustration: _The Field-bug._]

"The mother," says De Geer, "was accompanied by a troop of little ones,
sometimes as many as forty in number. She remained constantly with
them, generally on a twig or leaf. I noticed that the little ones and
their mother did not always remain in the same place, and that as soon
as the mother began to move to another position, all the little ones
began to run after her, and stopped whenever the mother halted. She
used to take them, as it were, for a walk from twig to twig, or from
one leaf to another, parading up and down the branches of the tree,
and she conducted them wherever she pleased, just as a hen does her
chickens. It frequently afforded me great pleasure to observe their
movements. One day I cut a young branch of the birch-tree inhabited by
such an insect family, and I immediately saw the mother, apparently
in great anxiety, begin to flap her wings violently, but without
attempting to fly away, as though she would frighten away her enemy. At
another time she would have immediately made her escape, thus plainly
showing that she remained only in order to defend her young brood."

As if to furnish an instance of precisely the opposite import, the
cruel and murderous father of this interesting little family is one
of the greatest enemies the poor mother has to contend against.
This hard-hearted parent does not hesitate whenever he falls in
with one of his children to seize him and eat him up! If the mother
spies him at this horrible feast she immediately attacks him in the
manner described; and does her utmost to deter him from his cannibal
propensities, by placing herself in an attitude of determined
resistance before him. Was ever mother's love more plainly manifested
than this love? No other instance of an affection so strange and strong
is to be found in the tribe to which she belongs.

The care of the earwig not only extends to her eggs, but also to her
young larvæ. "In the beginning of June," writes the author last quoted,
"I found under a stone a female earwig, surrounded by a number of
little creatures which I discovered to be her tiny family. She did not
attempt to leave them, and they frequently ran and crouched under her,
just as chickens under the wing of a hen. I took them up and placed
them under a sand-glass, under which I had put a little fresh earth.
They did not bore into the earth; and it was most curious to see them
running for shelter under the mother, and pushing about between her
feet, while she remained perfectly quiet. I fed them with pieces
of ripe apple, which the mother seized and ate with great avidity,
detaching morsels of it by means of her teeth, and swallowing them. The
young ones also ate a little of it, but with less avidity."

When the eggs of the spider mentioned in the last chapter as so
devotedly attached to its treasure as to prefer death to parting with
them, are hatched, they make their way out of the bag by an opening in
it, being assisted by the mother in this difficult task. De Geer indeed
states that this is the reason why the mother clings so tenaciously to
the bag of eggs, as if she knew that her assistance in extricating her
young from it was necessary. But this is not altogether correct, as
they are able to make their way out by themselves in due time. When the
young larvæ have come forth from the shell they run towards the mother,
and climb upon her body; some get on her head, some on her back, and
some on her limbs. In this manner she carries them about, and is said
to feed them until they become strong enough to shift for themselves.
"I have more than once been gratified," (writes one of the authors
of the Introduction to Entomology,) "by a sight of this interesting
spectacle; and when I nearly touched the mother, thus covered by
hundreds of progeny, it was most amusing to see them all leap from her
back, and run away in all directions."

For another instance of affection almost maternal for the young and
helpless larvæ, let us take a peep into an ant's nest. So soon as ever
the young larvæ emerge from the eggs they require the unremitting
attention of the best and most careful nurses in order to rear them.
They must be kept clean, fed, and taken for an airing as regularly
as the day returns. By means of their tongues, which are incessantly
used in licking them, their coats are kept of the most snowy white.
They are fed three or four times a day by their nurses, who take care
to masticate the food for them, and thus prepare it for their tender
mouths. But the most strange part is their regularly being taken out
for the benefit of the air and warmth. Some of the ants at the top of
the nest watch for the first beams of the welcome sun, and, as soon
as they pour upon the nest, they hasten down below in a great bustle
to wake up the nurses, and bid them take the young ones out of their
chambers and bring them up to the light, which these indefatigable
ants quickly set about to do. After basking there all day long the
nurses take care not to expose the delicate constitutions of the larvæ
to the chill evening air; and soon as the sun begins to sink towards
the horizon they carefully take them up and carry them to the warm deep
cell below. For fear, perhaps, of their taking cold, they never allow
them to be taken out in raw, damp, or frosty weather. It must not be
forgotten, however, that these ants are not the parents of the larvæ;
they are only the nurses.

But it becomes us now to pursue the more immediate subject of these
remarks, and ask the reader's attention to a few particulars about the
_larva_. It is a great pity, for the sake of a clear perception of the
facts of insect history, that there is a sad confusion of names in use
among the majority of persons in speaking of the different forms and
changes of insects. Who would imagine that caterpillar, grub, maggot,
and larva, signified one and the same stage of the life of an insect?
This abuse of terms cannot but render the knowledge of any science
less easily retained than it would otherwise be, for the question is
continually arising in the mind--If these all mean the same, why is
not one term enough to express them? Let us then renounce those of
uncertain meaning, and when we wish to give a name to the insect just
emerged from its eggshell, let us call it by its proper name, the
_Larva_.[C]

The larva, then, is the first form assumed by the insect on quitting
its shell. No more a little inactive object lies before us, as in the
egg and its slumbering tenant, but a sharp fellow, full of life, and
soon walking off the field of the microscope, should we happen to be
looking at it in that way, or from our book or table, should it be
there placed by us for observation. By what hidden and mysterious power
this has been effected who can tell? It was not heat alone that could
animate the contents of the shell, nor could all a mother's care do
more than preserve it from injury. It is very possible that chemistry
had _some_ share in it, and when the tiny being first awoke in the
shell the oxygen of the air undoubtedly was necessary to its health,
and the fulfilment of its early functions, but no more. Not chemistry,
nor electricity, nor heat, nor any other known force could effect this
wonderful change of apparently inanimate fluid into a lively, active,
and well-organized being; much less could either of these give it
its definite form, causing one larva to differ from another in its
characters. No, we cannot tell how it has taken place, nor what has
wrought the change; but we know the author of it--even Him who from the
beginning created all things, and established those principles which,
though hidden from our eyes, work out the marvels of the created world.
It is enough for us to know and to remember this. Should we attempt
more, we should probably fall under the Scripture reproof, "Professing
themselves to be wise, they became fools."

Speaking generally, insects in the larva form appear as fleshy worms,
having long and round bodies, marked with rings, and provided with a
head and a certain number of legs, mostly six. How different in this
condition, from the ballroom gaiety of the butterfly, or the elegant
robes of the lace-wing flies. To look at a number of larvæ, all
crawling over one another, and bearing perhaps not the most loving
behaviour to each other as they scramble about, who would dream that,
in a little while, those slowly moving bodies will be whirled through
the air faster than our feet can pursue, or even than the eye can
follow? Who also, but one well versed in the knowledge of insects,
could venture to say what insect could be formed by this or that larva,
now so little resembling winged insects at all?

[Illustration: _Larvæ unlike the future Insects._]

[Illustration: _Larvæ like the future Insects._]

In studying the forms and appearances of various larvæ, we shall find
that some of them bear a tolerably close resemblance to the future
insect; while others, on the contrary, do not resemble their future
condition at all; and had we to decide to what tribe of insects they
belonged, merely judging by their shape and character, we should be
sorely perplexed to do so, and if we did, we should often in all
probability be very far wrong. We need not go far for an illustration,
first, of a larva like the perfect insect, and next, for one totally
unlike it. Taking a candle and exploring into some snug hole near the
kitchen fire-place, we shall not be long, probably, before we extricate
a number of the larvæ of the cricket. Those of the bug also are very
like the perfect insect; so also are young spiders, cockroaches and
grasshoppers. These all resemble more or less perfectly the insect in
its complete form.

Even amongst the larvæ not resembling the perfect insect, a little
attention will enable us to perceive a sort of general resemblance
between those of different genera and species, which we may call the
Larva family likeness. This consists in the form of the body, in a
number of instances; but in all in the ring-like marks or segments
of the body, as they are called, which are _thirteen_ in number. If
the reader will take the trouble to count the rings in the larvæ of
different insects, he will generally find that they are thirteen in
number. The general resemblance of larvæ to one another may also be
noticed. The larva is, in every instance, destitute of wings. In many
cases, larvæ are provided with feet, in many others they have none. And
in some instances, they have no distinct head, as in the larva of the
blow fly.

[Illustration: _Larvæ of Butterflies._]

By far the larger number of larvæ belong to this class; that is, they
do not resemble the perfect insect. Do not resemble! could any one
believe that these strange, and some of them awful looking larvæ ever
became _butterflies_? yet they all belong to that tribe of insects.

[Illustration]

In order to give a clear conception of the structure of a larva, we may
briefly mention the names of its various parts. First then, there is a
_head_ of various shapes, sometimes of the shape of a heart, sometimes
round or triangular. Attached to the head are the two _antennæ_; or,
as they are commonly called, _feelers_, most probably an incorrect
expression, as it appears that insects may possibly _hear_ as well as
feel by their means. At the side of the head are the _eyes_, which are
formed much more simply than those of the perfect insect. Next is the
_mouth_, provided with its upper and lower pair of jaws. Then there is
the _body_ and its _legs_; and lastly, there is in many larvæ, living
in the water, a _tail_, which, strange to say, is provided with a
delicate tube, through which the larva breathes. A beautiful instance
of such an appendage to the body of the larva, is represented in the
adjoining cut; the various parts of the larva are also represented in
the accompanying figure.

[Illustration: _Diagram of a Larva._]

       *       *       *       *       *

We may now enter upon a few particulars connected with the general
history of insects in the larva form.




CHAPTER II.

HABITS OF THE LARVA.


Generally, for a little while after the larva has emerged from the
shell, it is in a very weak and languid condition. The effort of
extricating itself from its little prison-house, seems to leave it
almost without strength; and for a period which varies in different
insects, it lies helpless and almost motionless at the mercy of any
wandering adversary, and might be demolished without resistance. But
this hour of weakness, except in a few cases, is not prolonged. In
the course of an hour or two, or even much less in some instances,
the larva revives, takes heart, and begins by eating whatever food
may happen to lie in its way; and now the larva becomes a terror to
the world of insects, or even, indirectly, to man and to nations.
Instead of simply eating, in order to live, like most other beings,
it only lives to eat; it has no other duty to perform at present but
to eat as fast and as much as it possibly can in a certain time; and
it must be confessed, the larva, generally speaking, leaves little to
be desired on the score of a sharp appetite. Unlike other creatures
who allow themselves a certain period between their meals, the larva
sets to its feast and does not leave the table until it has devoured
all its contents,--upon which it immediately begins again elsewhere.
No _gourmand_ in the world, whether among human beings or brutes, can
compare with the insect in this form for the amount of food consumed.
Morning, noon, and night, is to it only a continued round of feasting;
and, as may well be imagined, the larva grows very rapidly accordingly.
Some larvæ consume animal, others vegetable food; or, in the language
of science, some are _carnivorous_, some are _graminivorous_ or
_herbivorous_, and some will eat anything almost that comes before
them--these would be called, and very appropriately so, _omnivorous_.

Let us speak of carnivorous larvæ first. The larvæ which have
carnivorous propensities render themselves often truly terrible to the
insect world around them. The most mighty warrior that ever lived in
his whole career never slew half so many of his own species as the
larva of a beautiful fly does of _aphides_ in a few hours. Well does
Réaumur call them the "lions of the aphides," and thus does he describe
their method of proceeding:--

[Illustration: _Lion of the Aphides._]

"There is no beast of prey in nature who hunts so entirely at his ease
as does this larva. Resting upon a twig or a leaf, he is surrounded on
every side by the insects on which he feeds; often, indeed, they touch
his sides, and he is able to catch hundreds of them without changing
his position. Not only do the poor little aphides not fly from him, but
they may be often seen creeping over the body of their enemy. It is
only after the larva has eaten up the greater number of his prey around
him, that he has any need to remove to a spot as thickly inhabited by
them as that in which he has been making his cruel ravages. In order to
observe the manner in which he attacks them, the best plan is to take
him, put him between two leaves, and shut him up in a box for ten or
twelve hours to sharpen his appetite. After this fast he must be placed
on some spot where the aphides are found in abundance. Immediately he
begins exploring around for prey, which he does simply by the sense of
touch, as he does not appear to be able to see. At length an unhappy
insect comes within his reach. Brandishing a trident with which he
is armed, he immediately transfixes the insect, just as we take up a
morsel of food upon a fork!" The little creature is then sucked into
a sort of cavity like the neck of a bottle, where it is retained by a
couple of pins until its juices are emptied by the destroyer, when he
casts it away, now nothing more of it being left but a dry, shrivelled,
empty skin. The aphis-lion, however, loses no time, and presently
seizes another, which he pierces and sucks dry as quickly as the
last.[D] When very hungry he will devour one a minute. Réaumur says, "I
have seen him eat twenty of these insects one after another in twenty
minutes; nor did this satisfy him: for in the course of two hours he
devoured more than a hundred insects with which I supplied him!" These
larvæ do repose a little, but never for long, for they are seldom
without some prey in hand. "I have seen," adds the last author, "twigs
of the elder seven or eight inches in length entirely covered with
these insects, (the _aphides_,) and in four days' time there remained
not one alive."

This larva is a rare specimen of courage, as well as of destructive
powers; for when it is quite young it often seizes upon an insect
twice as big as itself. It is very amusing to see the unequal contest
between the little but courageous foe, and his great, bulky, and stupid
adversary. Immediately the larva thrusts its trident into the body of
the enemy, who, stupid as he is, does not like the sensation of the
wound in his side, and makes off as fast as he can. The lion-hearted
larva follows him up and wrestles with him, and at length actually
boards him, to use a sailor's term, clambering up his sides, and, in
triumph, piercing him through and slaying him. What is perhaps most
singular of all, the larvæ of some species of these flies not only
slay their victims, but actually clothe themselves, after the manner of
Hercules on his victory over the Nemæan lion, with the skins of their
prey!

It is almost to be regretted that the insect world has not had the
privilege of having its combats sung by the poets. Who can forget the
animated scenes, painted in such life-like colours by Homer and Virgil,
of the conflicts, hand to hand, of the heroes of their verse? But the
history of insects supplies us with more singular and more interesting
deeds of fight than have ever yet been fabled by poets, or commemorated
in song. In the instance we are about to quote, the larva of the
ant-lion is the crafty Giant Grim, who lives by entrapping, as we have
before said, poor wayfaring travellers. Like those giants of old, of
whom we read in books a little more wonderful than true, this subtle
and powerful enemy lies deeply ensconced in his subterraneous cavern,
patiently abiding the time when his unsuspecting prey shall fall into
his power. His trap is depicted on the opposite page.

[Illustration: _An Ant-lion in its Trap._]

This insect is naturally a very helpless being, it can only walk at
a slow pace, and strange to add, it can only walk backwards, and not
forwards! Yet its food is the juice of insect bodies. How, then, is
it to seize upon them circumstanced so unfavourably as it is, having
neither swiftness nor ability to direct its motions sufficiently
actively to fit it for such a task? It succeeds by an artifice of the
most refined character. Nothing daunted by what we might call its
natural disadvantages, the insect sets bravely to work to construct a
trap for its prey; and the manner in which this is performed may well
strike us with wonder, and raise our admiration up to Him who has so
marvellously endowed this humble being with wisdom and skill. It first
takes care to choose out a proper site for the work it is about, and
in this always selects a soil composed of fine, loose, and dry sand,
well aware that, as we shall presently see, no other would be fit for
its purpose. Generally it chooses such a soil under the shelter of an
old wall, where the rain cannot easily penetrate and ruin its work. In
so doing it shows its wisdom; for thither, when the heat of the sun is
great, or when the rain-drops fall heavily, crowds of insects come for
shelter, and fall into its cruel embrace.

[Illustration: _Circular Ditch of the Ant-lion._]

The site being chosen, the next important step is to mark out the
bounds of its habitation, and with this view the insect begins digging
a circular ditch, walking backwards until it has completed the circle.
This defines the outer limits of its trap, and is a sort of guide line
to it in its future operations. Then it sets about the more proper task
of excavating its trap. Would that our readers could see this insect at
work! Of all the wonderful sights presented to us in the insect world
there is none to equal it in interest, none so calculated to enlist our
sympathies on the part of the patient, skilful, and unwearied little
labourers of this kingdom of nature. Guided by the line it has marked
out, the workman steps into the circle, and sets to work with a hearty
good will, and with a degree of diligence and excavating skill that
would put our railroad "navigators" to the blush. Shower after shower
of sand is seen flying up and beyond the boundary described, with the
most unintermitting diligence, until the insect has completed the
circle again; arrived there, it turns round and excavates back again
until it arrives at the same point. But it may perhaps be asked, where
are its tools, and by what means does it succeed in casting up these
loads of earth? We fear that at best any written description will
hardly do justice to our ingenious labourer; its method, however, is as
follows:--It uses the head as the spade, or rather shovel, and in the
strangest manner it fills the shovel with one of its feet with a load
of sand, and then by a quick movement of the head tosses it out of the
cavity. By working in alternate directions it manages so as never to
over-fatigue one leg, for on its return the leg previously in use is
at rest, while the one on the opposite side is now called into duty.
The insect thus works on until its trap is completely excavated, the
task occupying a variable time; sometimes being finished in half an
hour, sometimes even in less, but occasionally occupying several hours,
the little labourer being obliged to rest a certain time. Réaumur, who
has given a fascinating account of these insects, writes, "I have had
at times hundreds of ant-lions in a large box, and I have often been
amused with filling up their traps. Some of them would immediately
begin to form another; but the greater number in the warm long days of
summer deferred executing the work until the sun began to go down. They
seldom worked in the heat of the day; but in cold or cloudy weather
they would excavate at any hour."

We well know what perplexity a chain of rocky hills causes to a
railroad engineer, and what vast outlays of money, labour, and time
are necessary in order to overcome the obstacle thus presented to
the path of the engine and its train. But it may be safely said that
we can furnish a parallel instance of difficulty and of patient,
all-surmounting exertion from the history of the insect before us. M.
Bonnet was curious to know what it would do if a stone or some such
obstacle were met with in the process of its excavations, and one day
had the gratification of observing the behaviour of the insect under
these trying circumstances. Not being able to cast it out with its
head, the insect determined to carry it out, if possible, on its back.
With this view it contrived by various manoeuvres to place the stone
upon its back and to balance it there. This was the least difficult
part of the undertaking. The insect had to climb up an inclined plane
upon soil, chosen with other views purposely by itself, as shifting and
unsteady as possible, and not only so, but to preserve the balance of
the stone with which it was encumbered. Undaunted by these difficulties
it made the attempt, but the first step brought down a shower of sand,
and tumbled the little rock to the bottom. Again and again did the
heroic insect attempt the same feat, and with the same ill success, and
we might have thought we beheld a realization of the fable of Sisyphus
and the rolling-stone, in the vain endeavours of the insect to get
rid of its encumbrance. Five or six times did the insect repeat its
endeavours, and at last, after one or two narrow escapes, the stone was
fairly lodged on the outside of the trap, and the insect returned to
its subterraneous recess at the bottom of the cell in triumph.

The traps vary in size in proportion to the age of the insects which
construct them. The young insects only form very small ones; but as
even from the moment of their birth they are destined to toil for their
food, they do not wait in idleness and hunger because they cannot make
large efforts, but are content to make little traps not more than a few
parts of an inch in diameter. Thus they set us the needful example of
not despising to do small things because our strength is not yet equal
to the performance of as much as we could desire. The diameter of the
trap formed by a full-grown insect is about three inches; the depth
about two.

When its labours are over, it has been well remarked, the insect
now only requires patience--but it must have a good deal of it! It
generally buries itself, all but its jaws, in the sand at the bottom,
and here awaits its victims. If it requires much patience, surely it
also needs to have much power of endurance of hunger, for it may wait
for days sometimes without catching any prey. Frequently, when this is
the case, it marches out of its trap, and tries its fortune in some
more favourable spot. But see! an ant who has been out foraging for the
young ants at home is hastening back laden with sweet treasures, when
suddenly she finds her path arrested by what appears to her to be a
deep but smooth precipice. To plunge down and rise on the opposite side
is a shorter cut, in her estimation, than to go round; or perhaps she
is led by curiosity to wish to explore this singular cavity, and she
plants her feet on its treacherous edge, causing a few grains of sand
to roll down and give notice to the wary giant below that a victim is
at hand. A step back, and her life would be saved; but no, she leaves
the bank, trusts herself to the unfaithful soil of the sides of the
precipice, and instantly rolls down in a cloud of dust to the bottom.
Terror has now laid hold of her, and with all speed she strives to
clamber up the unsteady sides. For a moment escape appears possible,
but the Argus-eyed monster below starts up into activity, and piling
upon his head a huge load of sand, he shoots it after the escaping ant,
and once more brings her down covered with dust into his embrace. The
terrible jaws are instantly closed upon the unhappy insect, and in a
few minutes her existence is at an end, the savage enemy shaking her
violently, or dashing her quivering frame against the earth.

Singular to add, the ant-lion loves not dead prey, and will indignantly
cast it out of its trap. Says Réaumur, "They appear so much to delight
in the glory of a victory, that they disdain to touch an insect who
is not, to say the least, in a condition to contend with them!" It
certainly is not that the food when offered to it dead is not fresh
enough that it is thus treated; for if only killed an instant before
the insect still refuses to touch it. Réaumur is disposed to believe
that, like our sportsmen, these interesting but cruel insects destroy
prey more for the pleasure of exhibiting their superior skill, than
to appease their hunger. But it is rather uncharitable even to the
ant-lion, to say so much as this. When the insect has sucked all the
juices out of its victim's body, it casts it out of its trap, and the
earth around, strewed with dead bodies, is thus the silent witness to
the destroying powers of the giant within.

This singular insect, whose exploits have detained us so long, remains
in its larva form two years, growing daily in size until it has
completed its existence as a larva, and must then enter upon another
condition of life. It is to be regretted that it is not to be found in
England, or at least it has not been for some time discovered in our
island; but it is common in France and other parts of the continent,
and would well repay the trouble of being brought over. As the insect
is very patient of hunger, it might easily be conveyed in a little
wooden box, half filled with fine sand, and its proceedings could be
readily watched by placing it under a bell-glass, or in a little glass
case, introducing a few ants or spiders for its food from time to time.

The insect exhibits to us a wonderful instance of what we may call,
after the example of Dr. Paley, the principle of compensation in
nature. It can neither run nor fly with the speed necessary to overtake
its prey who are swifter of foot than itself. But God never created
it to starve, and has endowed it with a rare combination of faculties
by which it is enabled to live in the midst of plenty if not even of
luxuriance. So it is in a thousand other cases in nature. So it is
indeed in Providence likewise. If He sends us trials, "He also makes
a way to escape that we may be able to bear them." If our day is to
be dark and cloudy, and to call for the exercise of much faith and
patience, there is still the same provision made; "as thy day so shall
thy strength be." If our lot in life is one of hardship He can, and if
it is sought of him aright He will, and He does bear us up, revive our
drooping strength, and enable us to go on our way rejoicing.

[Illustration: _Cells of Sand-Wasp._]

Let us go on to speak now of some other carnivorous larva. If in the
month of July we can find out a spot where we can detect the traces of
the labours of the sand-wasp, of whom mention has been made at page
15, and cutting out a little mass of the sand-rock containing several
of their burrows, then take the trouble to open gently one of the
cells formed by these insects, we shall see a carnivorous larva in as
happy a condition as a fox in a hen-roost, or a mouse in the midst
of a cheese! The best way to obtain access to this securely imbedded
and luxurious larva, is to moisten the mass of sand with a little
water, and then slice it gently down with an old knife until we come
to the cells. They are here represented. At the bottom of each we
shall see the larvæ which have sprung from the eggs deposited in the
manner before described, after the arduous and affectionate labours of
the parent. Then above each is a heap of caterpillars, arranged with
beautiful neatness, and larvæ and caterpillars are both fast locked
in their prison house by the firm stopping with which the parent wasp
has closed the mouth of the cells. These caterpillars are all alive,
and are rolled into a ring-like form, but are so chained down that
they cannot move in the least degree. The poor prisoners, like the
sheep in the slaughter-yard, are only waiting their turn to be killed
and devoured. The larva soon after it is hatched finds himself in the
midst of a well-stored larder, and has nothing to do but eat, which he
does not long delay doing. He devours at his ease, and revels in the
dainty fresh food which the care of his parent had laid up. When he has
eaten all his prisoners up, and grown to his full size, he lays down to
sleep, to awake again in another and a far different form.

[Illustration: _Larva of Wood-boring Wasps._]

Sometimes the reader may have the opportunity, it may be, of finding
out the nest of the wood-boring wasp, and he may in June or July,
perhaps, succeed in discovering another instance of a larva in a happy
state of plenty. The larva is sure to be found at the bottom, and above
it will be piled a heap of insects for its food. What is remarkable
about this store of food is, that the insects thus made prisoners are
not dead, for they would, if so, soon become corrupted, and unfit for
the diet of the larva; they are in a sort of half stupified condition,
in all probability very like that induced by the late plan of breathing
ether and other vapours to render persons insensible to pain, while
surgically operated on. Since this plan has been introduced, we read
in some of the newspapers--we may question with what truth--that the
butchers in Albany (America,) give ether to the oxen before killing
them, so as to make them insensible to the pain of the death-blow! But
the wasps in question have for ages been in the habit of effecting the
same end by stinging their captives, the poison not sufficing to kill
them, nor yet permitting them to be actively alive.

The insects thus stored up for the larva cost the parent many a
conflict in their capture. And here we may interest the reader by
describing the exploits of a warrior wasp, abundant in the Isle of
France. It is curious that in the Isle of France the common bee is not
to be found as a native of the woods, while, in the Isle of Bourbon, it
is very common, and furnishes an abundance of wax and honey. This is
explained by supposing that the warriors of whom we are about to speak
destroy the bees, and have thus prevented their multiplying in the
island in question. Truly, like the banditti of whom we read in books,
these wasps are splendidly attired, although not in the spoils of those
they have robbed. Their head, chest, and body is of a resplendent
lustre; now green, or, seen in another position, blue, and glistening
with all the lustre of an exquisite varnish; their antennæ are black,
their eyes of a brownish yellow, and their legs partly bronze-coloured,
and partly of a beautiful violet. They are strong and swift of wing,
and are possessed of a terrible lance, the thrusts of which even man
cannot endure without far more pain and inflammation than attends an
ordinary sting.

The foe with whom these magnificently-dressed warriors have to contend,
is a kind of insect allied to the cockroach, which, in our kitchens,
has acquired the incorrect title of "black beetle." This insect is
detested by the inhabitants of the island, for its ravages upon almost
everything of value or delicacy, and is not less hated by the sailor
for its destructiveness on ship-board. It is called _Kakerlac_, and
is much larger than the cockroaches, which are the plague and terror
of our cooks. Imagine that one of these great and odious insects is
marching along the highway. The warrior wasp has also been making
his expeditions for prey abroad, when suddenly his eager eye catches
sight of the kakerlac hastening to some new scene of depredation. The
warrior instantly alights, and the kakerlac stops, thinking perhaps to
intimidate its adversary by its size and ferocious aspect. Both insects
glare at one another;--

                    ----"each other from afar
    They view, and rushing on, begin the war.
    They launch their spears; then hand to hand they meet,
    The trembling soil resounds beneath their feet;
    Their bucklers clash, thick blows descend from high,
    And flashes of fire from their hard helmets fly.
    Courage conspires with chance, and both engage
    With equal fortune yet, and mutual rage."

Virgil's description, though scarcely accurate in all points, gives us
a lively image of this insect combat. The kakerlac, however, is the
Turnus, and the warrior wasp the Æneas of the fight. The wasp is the
first to attack, and darts upon the other, seizing it by the muzzle
with its strong jaws, then bending its body so as to bring its tail
under the abdomen of the kakerlac, the lance with its charge of poison
is deep-plunged into the body of the unhappy foe, imbuing a deadly
venom into its system. Having made this thrust, the warrior looses the
foe, and soars in triumph a little way into the air, satisfied of a
successful issue.

The wretched kakerlac, after a few brief convulsions, lies paralysed
on the ground unable to stir a step from the spot where it encountered
its terrible adversary. Fully aware of this, the victorious wasp,
after taking a few turns, as if to proclaim the downfall of the Giant
Kakerlac to the surrounding neighbourhood, returns to the scene where
the conflict was fought. The kakerlac, unable to resist the victor,
and being naturally, though a great devourer, a very faint-hearted
creature, lies immovable while the wasp seizes the prostrate foe by the
head, and in a sort of triumphal march drags it along the road to its
nest. But though the kakerlac was not a difficult enemy to overcome,
the weight and size of its body are a sore burden to the victor wasp.
The way to the nest is long, tedious, and rugged. After a hard pull
over all sorts of obstacles the wasp becomes completely breathless,
and is obliged to let go, and for a rest it generally rises into the
air, probably with a view of reconnoitring future difficulties, and
of ascertaining the best route to pursue. Thus, after alternately
dragging along the body of its victim and rising up to spy out the
path, at length the conqueror succeeds in bringing the carcase home.

Here, however, arises another difficulty. To attempt to get the body
of the huge kakerlac in, is just as if one were to attempt to get an
elephant through a small street-door. What is to be done? The wasp
enters the hole backwards, and, seizing the head of the kakerlac,
endeavours with all its might to drag it in, but all in vain. Many
times it repeats these efforts with the same want of success; and now
it appears that its labours in bringing hither the corpse, and its
dangers in the battle, were all for nought, for the great body cannot
be put in the place the wasp had designed for it. As if exasperated
with the difficulties, out comes the wasp in fury, and falling upon
the body of the kakerlac, hews off the large wing-cases, together with
several of the limbs, and goes back into the hole again to repeat the
attempt to get it in. Success at length crowns its efforts; by little
and little the body becomes lost to sight, and finally disappears
altogether from view, being carried down to the very bottom of the
nest. Here the larva, as soon as hatched, feeds upon it, thrives, and
grows, and falls asleep, awaiting the time when itself shall awake to
follow in the steps of the glittering and formidable warrior who, with
the boldness of an amazon and affection of the tenderest of mothers,
supplied it with nourishment during its hours of infancy.

This may be thought a scene of sad carnage, but the following will,
perhaps, appear even more so. What should we say, if deep in the
forests of some wild uncultivated country was found a den, the bottom
of which was strewed with skulls, with bones, and mangled limbs? What
fearful scenes should we not suspect to have taken place in this dark
and horrid place; and as we shuddered in looking round upon its walls,
as the once witnesses of terrible deeds, we might even fancy we heard
the cry of the poor traveller, whose last agonies were seen by no eye
but that of the monster who had waylaid and murdered him? Such a den
may be found in the forest, made horrible by the cut-off heads, limbs,
and wings of insects--it is the habitation of the carnivorous larva
of a wasp. Nay more, as is seen in the engraving, the insect monster
actually works up the cut-off wings and limbs into a sort of covering
for itself, and finally buries itself in a shroud partly made of the
spoils of former victims.

[Illustration: _The Larva of a Wasp in its coat of wings and limbs._]

Perhaps the carnivorous larva of the tiger-beetle, or _cicindela_, is
as ferocious a being as any in this state. In this respect, indeed, it
resembles the perfect insect, whose title sufficiently indicates its
swiftness, cunning, and blood-thirsty nature. "These larvæ," writes Mr.
Westwood, "burrow cylindric retreats in the earth, to the depth of a
foot or more, employing their legs and jaws in loosening the particles
of sand and earth, which they carry to the surface upon their broad,
saucer-like head, ascending by the assistance of the two hooks upon the
back, somewhat after the fashion of a sweep going up a chimney! Having
completed this burrow, they station themselves, by means of their legs
and back hooks, at its mouth, their large flattened head and great
segment filling the hole." Here they remain all day long, and many an
insect might pass close by, little dreaming of the terrible foe who
lay under that trap-door. Presently comes a spider scrambling over
the ground in haste to mount up a branch on which to hang one of its
web lines; the treacherous trap-door is in its direct path. Its feet
rest on it; instantly the trap drops, and the poor insect falls into
the dark den, and is caught in the powerful jaws of the artful larva.
Truly, there is something even to man a little intimidating in the
sight of such a monster as is represented here; how much more to the
unfortunate insect who happens to be caught in its embrace, and having
only time to just catch a glimpse of its fearful captor, is dragged
down in a cloud of dust to be devoured in darkness at the bottom of
the den. Yet this also, like other cruel creatures, is in reality a
very timid larva, and instantly on the approach of danger, drops to
the bottom of the cell, where, if we have courage to pursue it, we
shall find it much in the attitude in which it is here represented. The
singular pair of hooks on its back are used as the flukes of an anchor
to sustain the insect in the position it assumes at the mouth of the
cell.

[Illustration: _Larva of the Tiger-Beetle._]

Mention has already been made in the previous chapter of the insects
called Ichneumons, which deposit their eggs in the bodies of the larvæ
of other insects. These, when hatched, are also to be reckoned among
the larvæ which prey upon flesh, since they devour the bodies of the
larvæ in which they have been deposited. They are thus most useful to
mankind in destroying the devourers of his vegetable food.

[Illustration: _Larva of the Dragon-fly._]

[Illustration: _The Mask partly open._]

[Illustration: _The same partly closed._]

We may now see an instance yet more strange of a carnivorous larva.
We must wend our way to the riverside in the months of May or June.
There, after a diligent search at the bottom, in some moderately
shallow portion of the stream shall we find a larva, the study of
which might well occupy us for many pages. Yet it is the larva of
an insect well known to every angler and brook-side wanderer--the
dragon-fly. This larva is provided with one of the most remarkable
contrivances for seizing its prey and conveying it to its mouth, of any
being in the zoological kingdom. By the assistance of the engraving,
we may perhaps be able to render this apparatus, which is somewhat
complicated, intelligible to the reader. Looking at the larva's head,
we are reminded somewhat of that of a horse who has got blinders over
his eyes, and a nose-bag over his nose, and partly up his cheeks.
Now suppose the two blinders thrown back on each side, then conceive
that the lower part of the face which we have supposed covered with a
nose-bag were to be uncovered, we should then see the following curious
contrivance. The lower lip of this larva is lengthened downwards into
a sort of _arm_, if we may so speak; at what we may call the _elbow_,
is a joint connecting the upper and lower portions of it, and the place
of the hand is occupied by two cross plates, with a claw at the end of
each. Suppose an unhappy insect, or even a tadpole, swims carelessly by
the larva, immediately the two sides of the mask, or blinders, as we
have called them, fly open; the arm is uncovered, the forearm let down,
and by means of the plates, which we have compared to the hand, the
victim is caught, and bending the arm back, is presented to the mouth
of the larva. There is much similarity in this organ with the wonderful
apparatus of the elephant called its trunk; but of the two, the trunk
of this insect is the most beautiful piece of animal mechanism. When
the prey has been devoured, the arm folds up, covers the mouth and part
of the face of the insect, and the blinders, or two side pieces of the
mask, fall in, and lock together in a toothed manner, as the engraving
in the last page shows.

[Illustration: _The apparatus in the act of seizing._]

Thus provided, the larva is a formidable creature to the inhabitants
of the pond or brook; few, indeed, more so. It preys with incessant
activity on all aquatic insects that happen to come in its way, and
sometimes, as we have said, even upon tadpoles. They do not even spare
one another, and woe to the unhappy relative of the family who happens
to wander near the abode of another of the same family, anxious to
begin his feasting for the day! So ferocious are they, that they
even attack small fish, and make little work of swallowing them up.
Not only are these creatures fierce, but they also possess all the
cunning of a tiger or a cat. To watch them seize their prey is an
interesting occupation, and as the larvæ are common enough, and may be
easily recognised by comparing them with the accompanying cut, we may
venture to recommend the amusement of observing their proceedings to
the reader. A little way off lies an unsuspecting insect delighting
in the warm sunshine, and securely floating upon the waters on the
corner of a leaf. Such an idea as danger at hand is probably the very
last from its conceptions, and pluming its bright and glossy wings, it
beguiles away the sunny hour unmolested by a passing enemy, or a breath
of air. The larva has marked it already for its own.[E] See it rouse
itself up, and noiselessly make ready to pounce upon the unsuspecting
lounger. It creeps stealthily along, concealing itself from view as far
as possible, and not even the tell-tale glassy surface of the water
feels its movements. Measuring its distance well, the larva prepares
to seize its prey; in a moment, swifter than the eye can follow, the
victim is caught by the apparatus we have described, and in another
instant, is in all the agonies of a violent death in the mouth of the
larva. So exceedingly cautious are these larvæ in their movements, and
so expert and active in darting upon their prey, that it scarcely ever
escapes their power.

[Illustration: _Cockchafer._]

[Illustration: _Larva._]

Having mentioned these particulars about carnivorous larvæ, let us
consider some circumstances connected with those larvæ that are
vegetable feeders--graminivorous or herbivorous. Of these, we could
scarcely select a more destructive one than the larva of an insect well
known to every school-boy from the times of Greece and Rome down to our
own--the common cockchafer, (_Melolontha vulgaris_.) Our schoolboys,
however, are less merciful than those of Greece, for _they_ only tied
a string round the leg of the unhappy cockchafer, while _these_
thrust a pin through its tail. Yet, its terrible ravages considered,
the insect little deserves to be pitied; but, we are not therefore
to be understood as by any means sanctioning the cruel and inhuman
sport alluded to. These larvæ are hatched in a sort of little cavern
dug by the parent insect's care under the ground in our meadows, or
corn-fields. Here they begin their ravages by devouring the roots of
the grasses which surround them on all sides. In this manner they very
quickly destroy the plants, which wither and die in a manner quite
mysterious to the agriculturist, if he does not happen to think of
these insects. The turf soon becomes so completely undermined by these
excavators, that it may be rolled off as smooth as if a knife had been
used underneath to cut off all its connexions with the ground. In a few
weeks, meadows which shone in all the fresh and luxuriant green raiment
of Spring, change colour, and before Summer has yet come, and before
the stalks of the grass are yet grown up, one would think Autumn had
passed over the face of the field, from its dry and dead aspect. About
seventy years ago, we are told these larvæ did so much injury to a poor
farmer's fields near Norwich, that the court of that city, out of
compassion, presented him with twenty-five pounds. Some idea of their
numbers on this farmer's property may be formed from the fact that the
farmer and his servant declared, with very long faces, we may be sure,
that they had gathered eighty bushels of them. Sometimes they even
attack the roots of young trees, and in this manner do an incalculable
amount of mischief to plantations. They were at one time so abundant in
France, and did such immense mischief, that the Government, in order
to get rid of them, offered a handsome reward for the best method of
destroying them. A number of experiments were made, and it really
seemed as if nothing would kill these larvæ, in the way of poison at
least, for several poisons which are rapidly fatal to man and animals
failed to produce the least effect on them. It was found, however,
at last, that a solution of alkalies, such as potash and soda, were
certain poisons to them, and should land be much infested with them, it
would be worth the trial to water it with such solutions, especially
as they tend rather to enrich the soil than otherwise. A French
manufacturer, determining to turn the visitation of these insects to
good account, has succeeded in distilling an excellent _lamp-oil_ from
their bodies, and offers tenpence a bushel for them. From seventeen
bushels he extracted twenty-eight quarts of good oil! In Hungary, a
kind of grease is obtained from them which is useful for carriage
wheels. The ingenuity of man may thus even procure good out of a very
formidable evil, although the mischief done by the cockchafer larva
undoubtedly far exceeds the benefit it confers upon its captors in the
amount of oil extracted from it.

An insect almost equally familiar to all persons is the long-legged
gnat, of whom the famous children's rhyme runs:--

    "'Old father long-legs' would not say his prayers;
    Take him by the left leg and throw him down stairs."

Many of our farmers would be glad, no doubt, if taking him by the left
leg would keep him out of their meadows, for there this insect commits
fearful ravages in the larva form. In some parts of England it has as
completely destroyed the pasture-grass as if it had been consumed by
fire. In the spring of 1813, hundreds of acres of pasture in the rich
district of _Sunk Island_ in Holderness were entirely destroyed by
it, being rendered as completely brown as if they had suffered a three
months' drought, and no other vegetation but that of a few thistles was
left on land, which, at more favoured periods, was more than commonly
luxuriant. On a square foot of the turf being dug up from the affected
spot, the enormous number of _two hundred and ten_ larvæ was counted
in it. Fortunately, the next year showed a very different result, for
then it was difficult on careful search to find one! In some districts
of France it is also very destructive, the grass of large tracts being
so completely destroyed by it, that enough food for the maintenance of
the cattle is not to be obtained. These larvæ, like the last-named,
appear to destroy by eating away the roots of the grass. From these and
the foregoing facts, entomology teaches us to regard these two insects,
upon which we commonly look with compassion, as occasionally becoming
the formidable, though indirect, enemies of man. The scientific name
for "Father Long-legs" is _Tipula oleracea_. The French call them
oddly enough milliners, or tailors, (_couturiéres, tailleurs_,) a
name of which it is harder to guess the origin than the common one
of father-long-legs, which is sufficiently expressive of one of the
features of the insect in the perfect state: perhaps the French tailors
are distinguished for being very long and thin!

[Illustration: _The Gamma Moth and Larva._]

We may yet linger awhile in the fields for another illustration of the
devouring propensities of vegetable-feeding larvæ. The pretty moth
represented in the accompanying engraving, together with its larva, was
once the cause of more alarm in France than we can readily conceive.
It is often to be seen in our meadows plunging its minute drinking
apparatus into the depths of the wild flowers, and flitting to and fro
at no great height from the ground all the day long, and even after
sun-down. It is called generally the Gamma moth, or _Plusia gamma_,
in consequence of the little mark in its wings, which resembles the
Greek letter [Greek: g]. Its larva is striped with green, and when
multiplied excessively, as was the case in France in the year 1735,
produces scenes of desolation which, as the results of apparently
an insignificant insect's doings, can scarcely be credited. In the
months of June and July in that year they became so numerous, that the
gardeners and peasantry in the districts plagued by them declared that
they must have been created by enchantment. In some places Réaumur
was assured that an old soldier had been seen to throw the spell. In
other places an ugly old woman, who was as wicked as she was frightful,
had caused all the mischief. Their prodigious numbers appeared to the
ignorant and superstitious peasantry an indubitable proof that they
were created by sorcery. And though we cannot, of course, sympathise
with their thoughts on this subject, we can well imagine and feel for
their astonishment and dismay as they beheld the wide desolation of
every green thing produced by the innumerable millions of these larvæ,
which covered forest, field and garden with their bodies. Many persons
began to fear they were really poisonous creatures, and refused in
consequence to partake of salads or other vegetable food of a similar
kind. This was probably an equal error with the last; and it is very
droll to find the talented Réaumur pleading with great earnestness that
the caterpillars were not unwholesome as food. He even declares his
opinion, that if these creatures were to become excessively numerous
in France, the inhabitants might be compelled to treat them as the
wretched inhabitants of Africa do the locusts, and when they have eaten
up every green thing, fall upon and eat _them_. With as much learning
and eloquence as if he was treating one of his most favourite topics in
entomology, M. Réaumur recommends these larvæ for human food, adding,
that a very little time would enable us to conquer our disgust at such
aliment, and that we should even welcome to our tables a dish of the
larvæ in question as an agreeable luxury! It is to be hoped, if ever
such a custom be originated, it will be confined to the place of its
birth--the country of this great, but, in this respect, whimsical
naturalist.

To account for their excessive multiplication, we have no need to have
recourse to enchantment for a solution of the difficulty. Each of the
gamma moths produces about four hundred eggs; now, if there were only
twenty larvæ in a certain locality which lived through the winter, and
became perfect insects in May following, the eggs deposited by these
would, supposing all to be hatched, produce, according to a calculation
made by Réaumur, in the course of a single year, _eight hundred
thousand_ larvæ. Well may we exclaim, then, with this learned author,
"Should we not rather wonder at the wisdom and forethought which has
ordered matters so that these insects increase to annoy us so rarely?"
The wonder is, in truth, not that they should multiply so excessively
at particular periods, so much as that it should be so seldom that they
are multiplied even to the extent of which they are naturally capable.
Thus, if we suppose that all the eggs of the moths of this species were
to be hatched, it is more than probable that a large portion of our
vegetation would be consumed by them. How is this guarded against? In
various ways. The eggs are not all capable of being hatched, or if so,
are not allowed to escape injury by various accidents, and the larvæ
themselves are a prey to countless enemies among the birds, while they
also frequently perish owing to the severity of winter. From these
considerations we may readily perceive how completely the well-being of
a great nation, with the lives of a large portion of its inhabitants,
are dependent upon the preserving, protecting, and restraining
influence of the providence of God. With the return of every year, we
may say, the question is asked by this tribe of insects alone, "Shall
we go forth to destroy and devour at once, or shall we refrain?" With
every year the silent reply is experienced by man in the unmolested
condition of his fields, gardens, and vineyards. "Oh!" we may ejaculate
with the Psalmist, "Oh that men would consider these things! then
should they understand the loving-kindness of the Lord."

[Illustration: _Destructive Larva and its Nest._]

Another and more remarkable instance of the destruction caused by
vegetable-eating larvæ may be quoted from the fertile pages of the
same illustrious naturalist, M. Réaumur, particularly because it is
the narration of one who was an eye-witness to the facts of which he
speaks. "In two journeys," he writes, "which I made from Paris to
Poitou, at the commencement of the month of September in 1730, and
also in 1731, I noticed that from Paris all the way to Tours every
oak, great and small, had been attacked by larvæ; the highest branches
appeared to be principally selected by them. Great isolated oak trees,
as well as those which formed dense forests, were alike attacked in
this manner, their summits being absolutely withered and dry. Had we
not known how greatly the larvæ may multiply, and what fearful ravages
they are capable of committing, one might have conceived that some hot
and blasting wind had reduced the leaves to this condition. In certain
districts, the hedges along the road-side had not a single leaf that
was not withered up." The engraving represents one of these mischievous
larvæ; it also shows the winter-nest into which they creep, and a leaf
which a regiment of them have already attacked.

Securely protected from the severity of the winter of 1731, in their
warm nests, these larvæ quitted them again early in April of 1732, to
set forth upon another mission of destruction. They had now multiplied
to a degree calculated to excite the most serious public alarm. It
began to be feared that the leaves of the trees would not be sufficient
for the support of the devouring millions; and that if, during that
year, the larvæ multiplied in the same proportion as in the preceding
year, a famine more terrible than any recorded in history as produced
by insect destroyers would be the result. These fears were in some
measure groundless, as, in all probability, so soon as the larvæ had
devoured all the leaves, they would rather have perished of hunger
than have attacked the grass and other plants. But the matter was
sufficiently serious as it was. The French parliament took the alarm,
and determined to resist the threatened invasion of these small but
formidable enemies. An edict was therefore issued, calling upon all
persons to assist in removing the larvæ from the trees, while they
were as yet not reinforced by the addition of countless millions
more. In orchards, gardens, and pleasure-grounds this became a far
from difficult duty, because it was easy to ascend the trees and to
remove the larvæ and their nests. But in dense forests, where the tall
trees waved high in the air, and where every branch and every twig was
loaded with larvæ, it was plainly impossible. Although, as we know,
acts of parliament are able to effect a great deal, these insects set
their powers at defiance, and little good was really accomplished.
Having thus, as it were, manifested to the nation how powerless were
their efforts to remove the plague, it pleased God to interfere by
his providence, and a succession of cold rains for three days in
May effectually stopped the progress of the destroyers, by utterly
annihilating them.

Réaumur's remarks well deserve extracting; he says:--"I had been hoping
much from the effect of these showers, and attentively watched what
would be the result. I saw day by day that among the little bands of
larvæ which were aggregated together in order to cover the twigs of
the trees with silk, or to despoil them of their leaves, there were
many whose bodies became flabby, elongated, and devoid of roundness.
These quickly perished. Every day the mortality became more serious
among them. In a short time the larvæ, which had previously swarmed
upon the trees, became so few, that before ten or twelve days had
passed by I could not find a single one, although I looked carefully
for them." It is remarkable enough, and sets forth strikingly the
short-sightedness and ingratitude of man, that these very showers,
which produced what no combined efforts of human power could or did
effect, were bitterly complained of as inappropriate to the season, at
the time when they were falling! These larvæ were hatched from eggs
deposited by a common species of moth.

Although England has been often mercifully spared while continental
countries have largely suffered by such visitations as we have last
described, we have not always come off unscathed. The larvæ of a moth
nearly allied to, if not the same as the last-mentioned, produced an
alarm in 1782 in our country, perhaps even more extensive than the
previous one in France. All sorts of strange and silly rumours were
spread abroad; some believing that the larvæ were the harbingers of
coming disease and death. Poor people were hired to cut off the webs
of these larvæ at the rate of one shilling a bushel, and they were
then burned under the inspection of the churchwardens and overseers.
In the parish of Clapham, we are told by an author who wrote upon the
history of this insect, _eighty bushels_ were collected in one day!
Prayers were offered up in some churches to deliver the country from
the apprehended approaching calamity.

We need not, however, dwell longer upon the vegetable-consuming larvæ
out of doors. Unfortunately we are acquainted with instances equally
formidable within our barns, store-houses, and larders. In vain does
man lay up the increase of his fields with care in granaries of the
best construction, and using all possible precautions against the
introduction of insect enemies. The weevil, called scientifically the
_Calandra granaria_, finds entrance, and in a short time makes its
presence felt in the vast destruction it produces. So soon as they are
discovered, they are collected with all expedition by the owners of the
stores and consigned to the flames for their misdeeds. Sometimes they
are collected thus by bushels, from which it may readily be conceived
what has been the amount of damage they have done.

There is a little moth whose larva is equally mischievous in
appropriating to its own use the food and property of man; its name
is the _Tinea hordei_. This fly, we are told, deposits perhaps twenty
or thirty eggs in a single grain; but as one grain only is to be the
portion of one larva, so soon as they are hatched they disperse by
mutual consent in a very amicable manner, and each selects its future
home, so that in a short time the whole family is comfortably lodged in
twenty or thirty distinct grains of corn. There, surrounded by food,
they live and thrive, eating up all the precious parts of the grain,
until nothing remains but the husk. They then fall asleep and enter
upon the further stages of insect development. No one could possibly
tell by the external appearance of the corn, that the least mischief
had taken place within, the fulness and general aspect of the grain
being the same; but on carefully examining it, a very minute hole may
be found in some spot or other;--it was here the enemy got in. We need
scarcely add, that for any purpose grain which has been thus attacked
is rendered perfectly useless.

Any one who has ever been on a long sea-voyage will find it easy to
supply us with another example of a vegetable-food devouring larva. The
hard substances commonly called captain's biscuits are the objects of
attack, together with flour, peas, and similar articles of food, and
the attacking insect is the larva of the meal-worm, the entomological
title of which is _Tenebrio molitor_. In vain does the ship's cook,
with all his art, prepare a soup composed of the richest ingredients,
and calculated, as one would think, to gratify the taste of the
greatest epicure. The larvæ have been beforehand with him; they have
attacked and become mixed with the flour or the peas; and when the soup
which has cost him so much pains is brought to table, not even the keen
appetite of seafaring people can reconcile them to it, for it is full
of the dead bodies of these larvæ. So likewise is the biscuit, and in
disgust the guests are compelled to confine their attention principally
to such articles of food as are unpalatable to their insect enemies.

We have but little experience, in our favoured land, of the more
extensive domestic destructions wrought by larvæ. But in hot countries
they become formidable, by reason of their numbers. In India,[F]
particularly during the rainy season, the interior of the houses swarms
with them; some climb the walls, some ascend the table, some feast
on the viands, and altogether, by their numbers and appearance, they
produce a degree of disgust and loathing at food, which cannot be
overcome for a long time by fresh residents. We may mention, before
concluding this part of our subject, that of those that do annoy us
domestically, some have appetites for very strange kinds of food, some
love wine, some vinegar, some butter and cheese; some revel in a pot
of preserves, some attack our meat, and one is mentioned by Réaumur as
delighting in _chocolate_!

If surprise be expressed that we have dwelt so long upon the eating
propensities of larvæ, let it be remembered that it was formerly said
at p. 94, that the principal duty of the larva, so long as it lived,
was _to eat_. It is born often only to eat as much as possible, and
to grow as large as possible within a given time; and in obedience to
this principle, we find larvæ with the sharpest of sharp appetites
embark in their career of existence, eating from their birth, all the
way along to their final change. It is therefore, obviously, a very
important part of the larva's history of which we have been speaking
for some pages past. Considering the fact to have been now brought into
sufficient prominence, we shall proceed to notice the rate at which
larvæ grow, and the actual quantities of food some of them devour. Let
us speak of the last first.

[Illustration: _Silk-worm Moth and her Eggs._]

Silk, as the youngest of our readers knows, is the production of a
little larva commonly called the silk-worm. Now, some years ago, the
calculation was made that in the United Kingdom alone was consumed,
every year, not less than five million pounds of raw silk. By means
of very accurate experiments, it has been ascertained that, in order
to procure one pound of raw silk, we must have twelve pounds of the
cocoons spun by these larvæ. In order to produce twelve pounds of
cocoons, one hundred and ninety-two pounds of mulberry-leaves must be
eaten up; or, which is the same thing, for every pound of raw silk,
we have to supply to the worms one hundred and ninety-two pounds of
leaves. We can now leave the calculation in the reader's hands; but we
may mention the sum total: it is, that for every year's consumption of
raw silk by our country, there is a certain consumption of _ninety-six
millions of pounds_ of mulberry-leaves; and as one hundred pounds of
leaves are calculated as the produce of one tree, it follows that nine
millions six hundred thousand mulberry trees must grow, in order to
supply food to the silk-worms necessary to furnish Great Britain with
silk for one year. Let us add, that this five million pounds of raw
silk is the production of the inconceivably great number of _eighteen
thousand million silk-worms_. The Count Dandolo, who has written an
excellent treatise on this subject, in Italian, made a number of
experiments upon the actual quantity of leaves devoured by the larvæ
hatched from an ounce weight of eggs; and he found that the quantity
of leaves consumed by them up to the completion of their development
as larvæ, amounted to upwards of sixteen hundred and nine pounds! In
a month from being first hatched, each larva consumes above an ounce
of leaves. As at first each larva only weighs the hundredth part of a
grain, it follows that it devours, in thirty days, about sixty thousand
times its original weight of leaves. If we suppose a puppy dog, just
born, to weigh a quarter of a pound, and to eat in the same proportion
for one month, it would have consumed, at the month's end, fifteen
thousand pounds of food. Could the puppy eat meat from the first,
which, as all are aware, he cannot, he would, at this rate, devour in
one month, from the time of his birth, one hundred and fifty sheep,
supposing each to weigh one hundred pounds; or about _five sheep_ for
his daily food! These calculations will show how voracious the larvæ
of the silk-worm are; and they are, probably, far from being among the
most voracious of the larvæ, only we are better acquainted with their
rate of devouring than with that of other insects in this state.

[Illustration: _Growth of Silk-worm Larvæ._]

All this eating cannot, of course, be unattended with a great increase
in the size of the larva. In some insects growth is prodigiously
rapid. A naturalist, who closely investigated this subject in the
common blow-fly, which is so apt to deposit its eggs upon meat in hot
weather, found that in the space of four-and-twenty hours, the larvæ
hatched from these eggs had increased to from one hundred and forty to
two hundred times their original weight. The larva of the great goat
moth, we are told by another, grows, altogether, to about seventy-two
thousand times its weight; but it takes three years so to do. In thus
growing, the larva becomes very fat and plump; and should it unhappily
cross the path of any bird, it would probably be nipped up as a dainty
morsel for the little ones in the distant nest. In birds, beasts, and
fishes, the rate of growth is much slower, and the amount of increase
much less. Fortunate is it for us that it is so; for what would become
of mankind if animals of the size of dogs could grow in a month to the
size of _elephants_, or young elephants to the size of _little hills_?
yet these comparisons are not exaggerated, remembering the increase and
growth of the silk-worm and of larvæ generally.




CHAPTER III.

MOULTING OF THE LARVA.


We are now to enter upon a very interesting part of the history of a
larva: this is called _moulting_, and consists in the larva casting
off its old skin, and appearing clothed in a new garment, often more
brilliant than before. The change is well and clearly described in
the following passage from the Introduction to Entomology, of Messrs.
Kirby and Spence:--"A day or two previously to each change of skin,
the larva ceases eating altogether; it becomes languid and feeble;
its beautiful colours fade; and it seeks a retreat in which it can
undergo this important and sometimes dangerous and even fatal operation
in security. Here, either fixing itself by its legs to the surface
on which it rests, or, as is the case with many caterpillars, by its
pro-legs, to a slight web spun for this purpose, it turns and twists
its body in various directions, and alternately swells and contracts
its different segments. The object of these motions and contortions
seems to be, to separate the exterior skin, now become dry and rigid,
from the new one just below it. After continuing these operations for
some hours, resting at intervals, without motion, as if exhausted by
their violence, the critical moment arrives: the skin splits in the
back, in consequence of the still more violent swelling of the second
and third segments. The opening thus made is speedily increased by a
succession of swellings and contractions of the remaining segments;
even the head itself often divides into three triangular pieces, and
the enclosed larva by degrees withdraws itself wholly from its old
skin." The engraving is intended to show the larva just escaping out of
its old skin.

[Illustration]

Sometimes the larva comes out of its skin at the side; sometimes it
has been seen to bite off portions of the skin. The most common way is
that above described. The skin, when cast in this manner, resembles a
sort of universal coat, which has fitted into every crack and joint
of the insect's body; and just as a lady's glove, if we could suppose
it tinted of a flesh-colour, and marked for the various markings on
the hand, might be mistaken, if cast down after inflating it with air,
for a hand cut off, so, only far more closely, does the cast skin
represent, in the minutest particular, the larva which has emerged
from it. It is a perfect mould of all its parts, even to the very
antennæ, eyes, jaws, &c. "Thus," say the authors last quoted, "if you
saved the skins cast by the larva of the insect called _Callimorpha_,
or _Arctia Caja_, you would appear to have ten different specimens
of caterpillars, furnished with every external necessary part, and
differing only in size and in the colour, perhaps, of the hairs, and
all representing the same individual."

In order to show how completely this is the case, some singular
experiments have been made by various observers, in the following
manner:--Just before the larva was about to cast off its skin, they
have, by means of a sharp instrument, cut off one or two of its feet.
The larva was then allowed to moult, and was carefully examined, and it
was invariably found that the feet cut off when in its old skin were
also wanting when it appeared in its new robes; thus plainly proving
that the feet were really sheathed in the old skin completely. It was
just as if we had gloves on our hands and were to put one finger or
more between a pair of sharp and powerful shears, we should, of course,
find that when we took off the glove we should be short of one or two
fingers!

But the hairs are not thus sheathed. The old skin, if the larva was a
hairy one, such as many of those with which we are familiar under the
more popular title "caterpillars," is cast off with the hairs attached
to it--a circumstance which makes the cast skin look still more like
the real larva. How, then, it may be asked, does the larva acquire
new hairs to take the place of the old ones? Were we to take a larva
just before its moulting, and by a sharp and delicate instrument, to
slit open and raise its old skin, we should soon perceive how this has
been contrived. We should there perceive sundry little tufts of very
delicate hairs, lying down smoothly on the surface of the larva's body,
and arranged in certain directions, with great regularity. When the
old skin is cast, in the course of a little time these hairs stand
upright, and assume precisely the same appearance as those on the
former skin.

The keeper of silk-worms can tell us well, and perhaps with many a
sigh, that the period of moulting is one of great peril to his tender
charge. The larvæ are sick and feeble for some time after each period
of moulting; and large numbers die at this time, apparently unable
to bear the exhaustion attending the loss of their old skin. Larvæ
generally are much debilitated by each moult that takes place; for a
variable period, sometimes for some hours, sometimes for a whole day,
they will refuse food, and lie without motion. All their parts are very
soft and tender, and require hardening by exposure to the air. After
a certain period, however, these effects pass off; the larva recovers
its original strength, its body becomes firm, its colour brightens, and
appears more brilliant than ever; and, above all, like convalescents
among ourselves, its appetite is twice as keen as before, which, when
we call to mind what has been already said about the voracity of larvæ,
it will be confessed, appears scarcely possible.

These changes of skin take place a definite number of times in the
larvæ of each species. The breeders of silk-worms tell us that that
precious, if not priceless, little larva, sheds its skin four times;
other larvæ moult oftener than these: some five times, some seven
times, some eight times, and some nine, or even ten times; others,
again, only moult thrice. The ordinary number of moults appears to be
about three or four. Some, however, never moult at all in the larva
state. The larva of the common bee, and that of the flesh-fly, and some
others, are among this number.

Whatever may be the general opinion upon the want of beauty and
comeliness in insects, and particularly during the larva stage of their
history, it is very certain that it is quite erroneous. We may possibly
fail, unaided by the pencil and colours of the artist, in conveying
even an approach to an adequate conception of the rich and glowing
raiment with which it has pleased God to clothe these minute and
humble beings. But a very little actual observation of a few even of
the commoner larvæ or caterpillars of the butterfly and moth species,
will convince the reader that few other created things have been so
exquisitely adorned with magnificence of colour and apparel as the
larvæ of these insects. Here will be found hues so rich and deep as to--

    "Make the rose's blush of beauty pale,
    And dim the rich geranium's scarlet blaze."

Here is a larva of a moth before us whose head is a delicate orange
colour, whose belly and feet a pale pure green, whose sides are of
primrose tint, variegated with slashes of green, and along the back
there runs a beautiful band of white, the intensity of which is most
agreeably relieved by a vein of lovely pink, which divides it in
the middle. There is another clothed in purple, green, and white;
another, the larva of the butterfly called the "Camberwell Beauty,"
is of a brilliant black, dotted with spots glowing like carbuncles
along its back; another has a coat which seems as if set with precious
stones, blazing with an intensity of colour which cannot be conveyed
by description. In a word, larvæ, on the whole, can boast as varied a
display of beautiful hues as can almost the whole array of flowers in
our gardens. In consequence of the, unfortunately, too general feeling
of loathing, to which allusion has already been made, but few persons
are in reality acquainted with their beauties. Their diminutive size
also renders them less attractive than they might otherwise prove,
since we are generally most pleased with the beauty of an object when
its size makes it so manifest to our eyes, as to render it impossible
it should escape our attention.

It is a very remarkable fact, and corresponds, to a certain extent,
with the influence of the same agent upon plants[G]--that light seems
to be in some measure necessary in order to develop the colours of the
larva. Thus it has been noticed, that those larvæ which are, by their
habits, much in darkness, dwelling, perhaps, in caves of the earth, or
immured in the heart of a piece of timber, or inhabiting a cell scooped
out of the solid rock, are, most frequently, of a uniform whitish
colour. Some experiments have shown that when these whitish larvæ have
been brought out of darkness and exposed to the sunlight, their colour
has turned to brown. Very probably this effect is due to precisely the
same kind of change as takes place when a fair-skinned European travels
into a southern clime, his face and hands becoming so brown, tanned,
and dark, as to form a ludicrous contrast to the whiteness of his
chest or arms, which are not exposed to the influence of the solar ray.

[Illustration: _Larvæ resembling Twigs._]

There is still something more to be said about the coats of the
larva. To look at some of them, it would be difficult for a person
unacquainted with entomology, to guess at the real nature of the object
before him. Some look like dry twigs. Some look far more like little
_Cactuses_ than insects. Some are clothed with _hairs_, arranged in
the most curious and eccentric manner. Some have hairs so long as
to give them all the appearance of very minute shock-dogs. In some,
the hairs are arranged like stars; in others, like the quills of the
"fretful porcupine." The backs of other larva look just as if they
were studded over with little camel-hair pencils. Madame Merian
has described the larva of an insect found in Surinam as having the
various divisions of its body ornamented with three blue tubercles,
like turquoise beads, from each of which proceeds a long, delicate,
feathery plume of a black colour. Another, described by the same lady,
is splendidly adorned on each side with fifty red tubercles, shining
like coral, from each of which proceed five or six long hairs. Some,
again, are covered as thickly as possible with sharp processes, like
thorns, sufficiently strong and sharp to pierce the skin of any one who
incautiously ventures to take them up. The body of a small caterpillar
brought from Brazil, is described by Kirby and Spence as possessing a
body so thickly planted with spines, like the branches of a tree, as
absolutely to wear the appearance of a forest or thicket in miniature!
It has been stated, indeed, by some travellers, that the larva of some
insects has the power of darting out, when alarmed by the approach of
anything, such as the human hand, from as many knobs or protuberances
in its back, eight bunches of little stings, with which it inflicts a
very painful and venomous wound.

[Illustration: _Singularly coated Larva._]

The larvæ of some insects again seem as if they were clothed from head
to foot in the most delicate and snowy white cotton wool. These may
sometimes be seen on our apple-trees; but one of the most singular is
figured in the cut, from an engraving given in Baron de Geer's work.
The larva is covered completely with a coat of cottony flakes of the
most dazzling white, and these are arranged, as will be perceived,
with great regularity. The larva has, in this white and warm raiment,
somewhat of the aspect of a coachman buried in the old-fashioned great
coats with the many capes.

Having dwelt so long upon the food and clothing of the insect in the
larva form, it is right we should now devote a little space to consider
how they _breathe_. Some one perhaps will say, _Breathe_?--do larvæ
breathe? Most certainly; and respiration, or the function of breathing,
is not more necessary to us than it is to these creatures. For this
purpose, however, we must begin a fresh chapter.




CHAPTER IV.

RESPIRATION OF THE LARVA.


We well know, from the various melancholy accidents which have taken
place, that unless human beings have a constant supply of pure fresh
air they must perish. Many years ago, a number of unfortunate persons
were shut up in a narrow cell, called the Black Hole, at Calcutta,
where they could scarcely find room to stand, much less obtain air to
breathe. In one night the greater part of them died. More recently, as
some poor Irish were being conveyed in a steamer in stormy weather, the
captain, out of prudence and mistaken kindness, ordered the hatches
to be all battened down, so that fresh air was prevented from getting
in. A shocking spectacle was beheld soon afterwards:--in the close,
suffocating cabin lay a number of dead bodies, of men, women, and
children, all destroyed by the want of air. Now, precisely the same
fatal results take place if we treat larvæ in the same manner; from
which we learn that undoubtedly breathing is not only one of their
functions, but a most necessary and important one.

This may be easily proved. If the reader will procure about a dozen
caterpillars of any common kind, and put them into a dry phial, corking
them closely up, and if he leaves them in their prison of glass a
sufficient time, all will die, even though he may have supplied them,
on putting them in, with an abundance of food. Clearly, therefore,
they do not die of starvation, and we should be naturally disposed to
say they must have died of suffocation; that is, they died because
the function of breathing could not take place, as there was not the
necessary change of the air contained in the phial. But suppose that
other caterpillars were procured and put into another phial, with a
sufficiency of green food, the mouth being covered over with a piece
of muslin, or fine lace, what would then be the result? Simply that
they would live and thrive for as long a period as they received their
proper quantity and quality of food, and would pass through all their
stages of existence as comfortably as if in the open air. The reason
would be because the open fibres of the muslin, or lace, do not
interfere in the least with the requisite change of air for respiration.

Again, if after corking up the bottle for a short time, we were to
shake out all the caterpillars from it, and then put into it a little
water, in which quick-lime has been slaked--sold by chemists under
the name of lime-water,--we should find it become quite white and
milk-like. This would be, because, as the physiological chemist well
knows, the function of breathing causes carbonic acid gas to be poured
out of the body, no matter whether it is the body of an insect or an
elephant; and this gas has the property of turning lime-water of the
colour mentioned. Hence we have a second and convincing proof that
larvæ breathe--we need scarcely remind the reader that caterpillars
are larvæ--and more than this, that the function of breathing in them
resembles, so far as the discharge of this peculiar gas is concerned,
the same function, whether carried on in the human body or in that of
the most mighty and majestic of the beasts of the field.

The great chemist, Scheele, has experimented, somewhat in the manner
we have recommended, upon the breathing of larvæ. He found that
when caterpillars and maggots, to use the customary terms for these
varieties of larvæ, were confined in vessels containing only about
eleven cubic inches of atmospheric air, and so stopped as to preclude
the ingress of any fresh air whatever, although furnished with an
abundant supply of food, they soon died. When he put them into a still
smaller vessel, they died the sooner. In fact, precisely in proportion
to the purity, or to the amount of the air contained in the space in
which he confined them, were their lives prolonged or shortened. He
found on examining the air that it contained, as above stated, carbonic
acid gas.

[Illustration: _A Spiracle open._]

[Illustration: _The same shut._]

We may, therefore, consider the question as settled--that larvæ do
breathe. Strange it may appear to some, but neither in the larva nor in
any other form of its existence do insects breathe by the _mouth_. How,
then, it may be asked? We shall now describe their breathing apparatus
very briefly. Along each side of the body runs a delicate tube for the
conveyance of air, called a _trachea_, or when both are spoken of, the
_tracheæ_; these channels run underneath the muscles and skin, and
open to the air by little branch tubes, the mouths of which are called
_spiracles_. Besides these branch tubes which open to the air, the
large tubes send off a great number of smaller ones, which extend to
all parts of the body, penetrating even to the legs and wings. In some
insects, the spiracles, or breathing holes, are defended by a pair
of flaps, which swing to and fro, so as to let in the air, and close
upon it after each inspiration. By this simple means the breathing of
insects is carried on; the air enters the tubes, passes along them,
and is then conveyed to every part of the body; after which, having
fulfilled its duties, it escapes again. In man, and the higher animals,
there is a separate place for the air in the body, which we call the
lungs, and here the blood is conveyed to the air, in order to be
purified. But, as we have just seen, in insects it is very different,
for in them the air is conveyed by innumerable minute pipes to every
portion of the frame. Such is the breathing mechanism common in larvæ
which live in the air.

It will be readily imagined that those larvæ which dwell in the water
must be furnished somewhat differently, in order to enable _them_ to
breathe. And here, as we shall now find, there are some very curious
arrangements, in order to effect this object. They may be considered
under two divisions. First, contrivances for breathing air while the
larva is immersed in the water; and, second, apparatus for extracting
the dissolved oxygen gas necessary for breathing from the water.

[Illustration: _Breathing apparatus of an aquatic Larva._]

Let us select a few of the most singular instances under the first of
these divisions. "No better example," write the entertaining authors
of the Introduction to Entomology, "can be selected than the gnat. You
must have occasionally observed in tubs of rain-water, numerous little
wriggling worm-like animals, which frequently ascend to the surface,
there remain awhile, and then bending their head under the body,
rapidly sink again to the bottom. These are the larvæ of some species
of the genus just named; and if you take one out of the water and
examine it, you will perceive that it is furnished, near the end of the
body, with a singular organ, which varies in length according to the
species, and forms an angle with the last segment but one. The mouth
of this organ is funnel-shaped, and terminates in five points like a
star; and by this it is usually suspended at the surface of the water,
and preserves its communication with the atmosphere. In its interior
is a tube which is connected with the _tracheæ_, and terminates in
several openings, visible under a microscope at the mouth of the organ.
The points or rays of this mouth are used to close it when the animal
is disposed to sink in the water, and thus cut off its communication
with the atmosphere. When the animal is immersed, a globule of air
remains attached to the end of the tube, so that it is in fact of less
specific gravity than water, and it is not without some effort that it
descends to the bottom; but when it wishes to rise again, it has only
to unclose the tube, and it rises without an effort to the surface, and
remains suspended for any length of time. The extremity of the larva is
clothed with bunches of hairs, which are furnished with some repellent
material which prevents their becoming wet. It is this repellent
quality that probably causes a dimple or depression of the surface,
which, if you look narrowly, you will discover round the mouth of the
tube."

In summer time, the reader can scarcely fail of the gratification of
watching these most curious creatures, for they abound in ditches,
pools, and the stagnant waters of artificial fountains. They form a
very curious object under the microscope, and particularly in the
gas microscope, or solar microscope, where the image of the larvæ is
thrown, as in the case of the magic-lantern, upon a white sheet, or
wall. Their curious writhings to and fro, the energy they display in
lashing about their tails, so as to throw the few drops of water in
which they are imprisoned into mimic whirlpools, their occasional
dartings down to the bottom, and subsequent gentle rise up to the
surface, together with the terror into which countless minor occupants
of the same watery prison with themselves are thrown, when one of these
comparative giants plunges into the midst of them, form a spectacle as
unique as it is interesting and diverting. A sharp eye, and a phial and
cork, are the alone requisites for finding out these singular beings
on most fine days in summer. But a little while ago the writer was
amused to find, on a sunny day in June, the water of a small fountain
playing before his study window, thickly populated with these active
larvæ, and it became an amusement which seldom wearied, to watch their
fantastic evolutions, and to trace their changes from the larva through
the ulterior stage up to the perfect insect. To this, however, we shall
probably have occasion to revert before the conclusion of this work.

Another instance of a curious contrivance for assisting the breathing
of a larva, whose body is wholly immersed in water, may also be found
near home. Most probably the majority of our readers have seen, or
at any rate are well acquainted with the apparatus by which the
diver descends and works under water. Lest some should not, we may
mention that it consists of a water-tight dress, which covers the
diver from head to foot, while his head is enclosed in a helmet, or
hood, furnished with a pipe or hose, which is long enough to reach
to the surface of the water, and is there generally connected with
an air-pump, which forces down fresh air, and so enables the man to
breathe almost as comfortably as if he were walking on land, instead
of at the bottom of the sea. Let it be conceived now that there were
no air-pump at the top of the hose, but simply a buoy of cork to
keep it floating, and that the diver had the power of shortening or
lengthening the hose at his pleasure, we should then have a tolerably
fair representation of the contrivance with which Infinite Wisdom has
supplied the humble creatures of whom we are about to speak.

By carefully examining the water running from manure heaps, or water
which has become putrid, and is much loaded with mud and ooze, the
reader will pretty generally be successful in discovering a number of
the larvæ of a two-winged fly of the shape represented in the cut.
When discovered, the singularity of their structure will amply repay
him for the trifling unpleasantness attending the search after them.
After washing them in a little fair water, and putting them into a tall
ale-glass, or German beer-glass, which must be three parts filled with
water, they will be in the best condition for our examination. When
Réaumur first beheld them, he gave them the name of _Vers à queue de
rat_; that is, larvæ with a rat's tail; and when the reader looks at
them, as shown in the representation annexed, he will be inclined to
think with us, that a more appropriate title could not have been found.

[Illustration: _Rat-tailed Larvæ._]

On watching them they will be seen to wriggle about until they are
comfortably settled, darting from place to place, as if uneasy in their
new position and in the pure element. By-and-by, however, they become
reconciled to their lot, and lie perfectly quiet at the bottom of the
glass in the position represented. From the tail of each will now be
seen to rise a beautifully delicate and minute tube, which comes up
to the surface of the water, and here, whatever be the movements of
the larva below, it remains floating and free. Just as the diver may,
while his companions above are pouring down torrents of fresh air,
move about, and perform various duties under, water, so the larva
may move from one position to another, and assume almost any variety
of attitude; but its little air-pipe still retains its perpendicular
direction, and does not quit the surface of the fluid.

A singular experiment may now be tried with them. Let a little water be
poured into the glass by means of a funnel, the end of which dips under
the water so as not to give them unnecessary disturbance, and by this
means the level of the water in the glass becomes insensibly raised
half an inch or so. In a few seconds it will be found that these little
tails have all lengthened themselves, and are again at the surface
of the water, even at its higher level. More water may be poured in
until perhaps the level is raised three or four inches, and still the
same thing takes place, the larvæ still prolong their curious tails,
until it seems as if they would stretch to an indefinite length, for
they are already eight or ten times longer than the body! But, as we
might jestingly say--the longest _tail_ comes to an end at last; for,
on continuing to pour more water in, the larvæ stretch their tails to
the utmost, and then, finding the level of the water still above their
reach, they become uneasy, and all quit the bottom of the glass and
attach themselves to its sides.

[Illustration: _The Tail magnified._]

Let us now examine more minutely this very singular apparatus. By a
good lens we may readily do this, as the organ is very transparent,
permitting its internal structure to be beautifully seen. Placing the
creature in a convenient position for our examination, and in a good
light, it will be presently seen that the tail is composed in reality
of two tubes, of which one slides up and down within the other, just
like the tubes of a telescope (see cut). By this means the larva is
provided with an instrument capable of being made to reach to a great
length, and yet also possessing the capability of being packed up again
in a very small compass. The proper breathing tube is the small inner
one; at its extremity is a pair of spiracles, or breathing pores, and
surrounding these are placed five minute bristles, which are supposed
to act somewhat as a buoy, and to retain the tail in its position.
Where the tail joins on to the body of the larva, two tubes thrown into
folds are placed, which are connected with the breathing tubes of the
tail, at one end, and with the breathing pipes which run along the body
of the larva at the other. When the tail is pushed out to its farthest,
these zig-zag tubes are stretched quite straight; when it is drawn in
again, they are thrown into folds. Both these appearances are shown in
the plate. It has been supposed that the larva causes the tube to be
pushed out by forcing air into it, and thus causing the zig-zag tubes
to straighten themselves. Perhaps the tail is drawn in by the same
tubes contracting again, and thus folding together and dragging back
the tube to which they are connected.

[Illustration: _End of the Tail._]

We need scarcely stop to mention how useful is this admirable
contrivance to the insect. Having to seek for their food at the bottom
of ditches, drains, or puddles, they are necessarily exposed to the
risk of suffocation, unless fresh air can be conveyed to them; and
it is difficult for us to imagine how any apparatus could have been
contrived which would have adapted itself to all the varying depths
of water in which the insect must be constantly living, as it changes
from place to place. He must have been a clever engineer who could have
successfully met this difficulty. None of our present diving apparatus
does so. The organ we have been considering, the creation of an
Infinite Mind, small and despicable as it may seem in our eyes, fulfils
perfectly every function for which it was formed. It admits of free
movement from place to place, it admits, moreover, of free change from
one level to another in the fluid by which the larva is surrounded,
and it is at the entire disposal of the insect, which can, without the
smallest inconvenience, accommodate it to the various circumstances in
which it may be placed.

[Illustration: _Chameleon-fly Larva._]

Possibly the same phial in which was brought home the last-named
larvæ with the rat's tail, will furnish us with an equally elegant
instance of larva-respiration under water, in the case of the larva of
a fly, called the chameleon fly. This little creature, if it can be
found, and though not as common as the last, it may yet be detected,
in summer by the edge of ponds, &c., has truly elegant habits. The
great Swammerdam, who first described it, was lost in admiration at
it. The extremity of its body is furnished with a coronet of about
thirty elegantly feathered hairs. These are under the control of the
insect, and are capable of being folded up, so as to enclose a minute
bubble of air. When the larva is weary of remaining at the top of the
water, and wishes to dive to the still and cool depths below, it causes
these hairs so to fold up and close upon each other as to include the
air-bubble, so that it cannot escape. Thus furnished with a pearl in
its tail, it plunges downward, and thus breathes under water until the
purity of the captive air-bubble is impaired, when it returns to the
surface to repeat the same operations. The appearance of the little
bubble shining, with a brilliant silvery lustre under the water, is
very pleasing, and accounts for the enthusiastic expressions used
by Swammerdam, in speaking of the visible manifestation of the skill
of God in this insect. The fact of an insect coming to the surface
for air, and stealing away a portion, then diving down again into the
waters, is not uncommon in insect history, although few are possessed
of so elegant a contrivance for effecting it as the larva in question.

We must pass on to mention an instance or two of larvæ which, from
the peculiarity of their respiration, come under the second of our
divisions, that is, they live in the water, and do not breathe air, but
obtain the gas necessary for their respiration _from the water_, which
holds it in a state of solution. We shall first speak of the larva of
the common May-fly, the perfect insect of which is so well known to,
and highly prized by, anglers, under the various names of "duns" and
"drakes," than which in some streams no insect that flies is a better
bait to the unwary fish. Should the reader wish to examine them for
himself, they may be found in May or June, hiding themselves during
the day in the mud, or underneath stones, or in little holes in the
banks, or taking a sub-aqueous tour upon the bed of the brook, while
the clear and purling waters roll smoothly on above them. Their little
under-water cells are shown in the cuts, together with the larva.

[Illustration: _Cells of May-fly Larva._]

[Illustration: _Larva and section of its cell._]

Their organs for breathing the water, if the expression, which is in
some measure correct, may be admitted, are very like the gills of a
fish. But instead of forming a part of the structure of the mouth
and head, as those of the fish, in the larva they are placed along
its body, and are arranged in pairs. A delicate little air-tube
enters into each of these gills, and there branches out into a great
many directions; this tube is connected with the large trachea,
or breathing vessel of the insect, running along its body. The air
entering these gills, and thus being exposed to a large surface of
water containing dissolved gas, loses its impurities, and absorbs the
pure gas from the water, whence it is then conveyed to the various
parts of the body. In many species of these larvæ the whole series
of gills are moved to and fro incessantly, and so quickly as to be
scarcely perceptible to the eye. Some of them use them as oars,
moving with inconceivable rapidity, and being capable of darting both
backwards and forwards with great quickness. They have also the power
of leaping or springing in the water to a considerable distance; and
feed on minute aquatic larvæ, and on vegetable matters.

The only other instance of this kind that we shall quote will be that
of the terrible larva of the dragon-fly, whose deeds of insect murder
came before us on a former occasion. The apparatus provided for them
is very singular, and has been described with his usual accuracy by
the talented Réaumur. It exists in the tail of the insect, and may be
readily watched in action by adopting the following expedient:--Pour
into a small glass, in which the larva has been put, and which is
half full of water, a few drops of a solution of carmine, by means of
a little tube introduced into the water, and made to drop its contents
near the tail of the creature. Immediately it will be seen that the
coloured liquid is rapidly sucked in by the tail of the insect, and
then, after the expiration of a little time, is forced back again
in a tiny jet, with considerable violence, to a distance of several
inches.[H] Réaumur tells us, that if we hold the insect between the
finger and thumb gently, and let fall a drop of water on its tail,
we shall presently see it eagerly sucked in, the body of the insect
becoming sensibly larger; and by-and-by it is thrown out again.
Sometimes it raises its tail above the surface of the water, and,
whether for sport or not, it is hard to say, squirts the water in a
mimic jet to some distance.

The apparatus has been described as resembling the piston or plunger
of a force-pump, which moves to and fro within a cavity inside the
insect's body, and by that means draws in and forces out the water.
The tail is defended by a sort of coronet, composed of five hard
bristle-like pieces, which are under the control of the creature,
and may be opened and closed at pleasure. The larva appears capable
of inflicting a somewhat painful pinch by this contrivance, so that,
what with its wonderful mask, with its powerful squirt, and with its
tail thus armed, it would be difficult to select another insect better
prepared for battle with creatures of every aquatic tribe than it.
The action of the pumping apparatus sends it rapidly forward through
the water, somewhat like a paddle-wheel, or at least upon the same
principle as that contrivance, namely, the resistance offered by the
water to the stroke of this apparatus.




CHAPTER V.

MEANS OF DEFENCE OF THE LARVA.


There is, perhaps, no period in the life of an insect when it is
so much in danger of the attacks of foes, as when it is in the
larva state. Possessed, at the best, with but very feeble powers
of locomotion, in comparison with those of winged insects, it is
continually exposed to destruction on all sides, from which it has
not the power to escape. Not only do insects of various species
particularly select the larva for the object of their attacks, but
birds and other creatures are also in the lists against them. Thus
imperilled, what chance has the larva against foes so numerous, and in
a contest so unequal? It has been calculated that a pair of sparrows,
for their own consumption, and for that of their tender brood, destroy
at least three thousand caterpillars in a week! and we well know what
multitudes of larvæ fall into the clutches of the cawing rooks which
follow the tail of the plough. The winged insects are tolerably secure,
although many even of their ranks fall victims to the swift-winged
swallow and sand-martin, and to the rapid leap of the artful trout. But
the poor crawling larvæ are neither strong enough to fight, nor swift
enough to flee, and fall by thousands into the unsparing hands of their
various enemies.

[Illustration: _Leaf-rolling Larvæ._]

[Illustration: _Larva Case of Shells._]

Yet, the Creator, who has wisely appointed a large portion of their
numbers for food to many creatures, has also taken many precautions
to prevent their being entirely annihilated, as might otherwise have
been the case. These are well deserving a brief notice, previous to
our passing on to the last stage in the history of the larva. From
what has been already said about the coats of various larvæ, it may be
imagined that that must be a stout-hearted enemy which could venture
to attack some of them. The spines and hard excrescences with which
they are furnished must, undoubtedly, prove far from agreeable to the
touch of a foe; and there can be no question that this sort of armour
is, of itself, a good defence to many larvæ. Others form artificial
coverings, which are equally useful, by concealing them from the
notice of their enemies. Thus, as we have before remarked, some dwell
in tubes of leaves, hid from every eye; others encase themselves in
a shield of cemented gravel or shells, like those represented in the
cut, presenting a most grotesque appearance; others hide themselves
in variously-formed cells. Some, immediately on being touched, roll
themselves up, like hedge-hogs, into a ball, which looks like a little
globe of hairs, and is so slippery that it cannot be retained between
the fingers; others, again, when they are touched, instantly drop down,
and from their colour, resembling precisely that of the herbage into
which they have fallen, it becomes next to fruitless to search for them.

A very singular larva which, both for offence and defence, adopts
a most extraordinary procedure, must be mentioned by itself. This
larva is not unfrequently to be found in our houses, and is said to
feed upon our disgusting and annoying invaders--the bugs; but it so
completely contrives to conceal its real character, that not once in a
hundred times would it, probably, be recognised as an insect at all.
It collects together a number of particles of sand, or fragments of
wool, or silk, or earth, and with singular skill, contrives to form a
sort of coat out of these, in which it envelopes itself. Thus attired,
as may be imagined, it is not easy to discover what the object really
is, and it thus, undoubtedly, escapes the undesirable notice of any of
its enemies. But more than this: like those North American Indians,
who hunt by concealing themselves in the skins of wolves, and so
attract less attention from the herd than they would do if they were
to expose themselves in their natural aspect to view, this crafty
larva steals upon its prey in much the same manner, although it can
run with sufficient swiftness when necessary. It creeps forward with
the greatest stealth, moving only one leg at a time, and thus quite
insensibly approaches its victim, who is not at all alarmed at what
merely appears to be a lump of dust. Soon, however, it is convinced of
its fatal mistake, and discovers the terrible fact that it is in the
embrace of an unsparing devourer.

Other larvæ escape notice in a singular manner, by their close
resemblance to little pieces of stick. Thus, we are told by Messrs.
Kirby and Spence, that "there is a certain tribe of caterpillars called
surveyors (_Geometræ_), that will sometimes support themselves, for
whole hours, by means of their posterior legs, solely upon their hinder
extremity, forming an angle, of various degrees, with the branch on
which they are standing, and looking like one of its twigs. The body is
kept stiff and immovable, with the separations of the segments scarcely
visible; it terminates in a knob, the legs being applied close, so
as to resemble a bud at the end of a twig; besides which, it often
exhibits intermediate tubercles, which increase the resemblance. Its
colour, too, is usually obscure, and similar to that of the bark of a
tree: so that, doubtless, the sparrows and other birds are frequently
deceived by this manoeuvre, and thus balked of their prey. Rösel's
gardener, mistaking one of these caterpillars for a dead twig, started
back in great alarm, when, upon attempting to break it off, he found it
was a living animal."

Some, however, are actually armed, so as to offer an active resistance
to the onslaught of any enemy. Mr. Abbot has described a terrible
caterpillar, well known in certain districts in America, under the
strange title of the "Hickory-horned Devil." This creature is furnished
with seven or eight strong horn-like spines, upwards of half an inch
in length, which project from its head and anterior segments. When
threatened by danger, the caterpillar does not attempt to fly, but
lifts up its head menacingly, and shakes it about in a very fierce
manner. The negroes, in particular, are so terrified at its aspect,
that they dread it as much as the rattlesnake. But, in reality, it
is harmless; and Mr. Abbot, in order to convince the ignorant people
that such was the case, took hold of it, in their presence, without
receiving any injury. This, however, did not convince them, and they
made answer that, although it did not sting him, it would undoubtedly
sting them.

The weapon of another is thus pleasantly described by De Geer:--"In the
month of July, I found a caterpillar resting upon a small twig, which
I cut off in order to enable me to examine it more attentively. As I
was scrutinizing its appearance, I happened, accidentally, to touch its
body. Instantly there shot out, from a spot near the head, two streams
of clear fluid, which struck me on the face, and partly entered one of
my eyes, causing a very acute, but fortunately, not a very enduring
pain. My surprise at this salute prevented my taking particular notice
of the place from whence the jets proceeded. It appears probable that
this caterpillar has been thus endowed with this squirting apparatus to
enable it to defend itself against its enemies, or at least, to assist
in frightening, or perhaps in hunting, its prey. For myself, I confess,
after the reception I had met with, I felt some degree of fear at too
nearly approaching it."

[Illustration: _Squirting Larva. The Cleft and squirting Organ are
shown separately._]

On examining them carefully at another opportunity, this entomologist
found that these caterpillars were provided with a squirting apparatus,
situated in a cleft in the neck. When the creature is irritated, it
thrusts out a curious organ, divided into four branches, and drilled
with holes, like the rose of a watering-pot. From this organ shoot the
jets of fluid spoken of. After the discharge they are drawn in again,
and covered over by the closing up of the cleft. Strange to say, when
taken in-doors, the caterpillar lost the power of squirting altogether.
It appeared as if it could only do so in the open air, where a number
of insect enemies were arrayed against it. This caterpillar is commonly
known as that of the Puss-moth, and has sometimes caused the most
strange and foolish country tales by its striking appearance. It has
been described as a horrible monster, having a head like a lion, jaws
like a shark, a horn like a unicorn, and two tremendous stings in its
tail! Certainly, its appearance is not the most engaging in the world,
as may be conceived from the representation of it in the cut; and what
adds to its singularity is, that it possesses the power of lashing its
sides with its tail, so as to drive away flies. If the reader should be
fortunate enough to find one, he may have some amusement in examining
all the curious apparatus with which this rather forbidding looking
insect is supplied.

The winter draws near, and sends its foretokening cold breathings to
warn every creature, vegetable and animal, that the dark season is
arriving, when food is no longer to be obtained. What is to become
of the larva? Can it endure the penetrating tooth of frost, or the
overwhelming shower of rain? Or can it endure to be from week to week,
from month to month, without a mouthful of food? From the facts already
stated with reference to the age of larva, it is very certain that many
larvæ have to bear these trials; and some, not merely during one, but
during several winters. We must, therefore, inquire how they have been
defended, or strengthened, so as to enable them so to do.

[Illustration: _Shaggy-coated Larvæ._]

The alteration in the coats of animals during winter, or rather, just
previous to it, and the fact that animals destined to inhabit the
arctic regions are enveloped in coats of the shaggiest hair, are well
known to every person. There can be no doubt, that in many instances
in the insect world, where a larva has to be exposed to the frosts of
winter, the same provision of a hairy covering, which has been given to
them by the Creator, is intended to meet the same end, and to preserve
their soft and tender bodies from the destructive influence of extreme
cold. The following striking observation of a talented entomologist,
who has not thought it beneath him to write a most interesting book
only on the family of ants (M. Huber), shows very clearly that such
is, in fact, the intention of providing the larva with a covering of
this kind. He noticed that the larvæ of some species of ants destined
to pass through the winter, were furnished with this kind of warm
clothing, while those which were not so destined had smooth coats, that
is, even in the same species: thus proving to us, beyond a doubt, that
as the winter approached, the warm coat was put on by the larvæ. The
engraving on the last page represents some extraordinary specimens of
hairiness in caterpillars from Brazil, now in the British Museum.

A large number of larvæ become torpid during winter--they are not
dead--they are not sensibly alive--they are plunged in that long
half-death which affects not only them but also many large animals,
who retire in winter, lie down to sleep for weeks, and awake to
find the cold departing, and the spring-time nigh at hand. But the
frost sometimes proves too severe for them, and the poor insects
become sometimes congealed into solid lumps of ice! Alas! we shall
exclaim, then there is an end to their life when that takes place;
and, undoubtedly, the severity of such a degree of cold destroys large
numbers; yet, strange to say, some larvæ actually revive, even after
they have been thus frozen into hard inanimate lumps. One observer
states that he has found them in this condition; and so entirely
congealed, that they chinked like small stones when dropped into
a glass tumbler! yet they revived after careful management. In an
experiment made during Sir John Ross's voyage to the arctic regions,
upon the larvæ of a moth, they were four successive times exposed to
the intense cold of 40° below zero, and four times they revived again
on being brought into the warm atmosphere of the cabin. Experiments
have also been made by other persons with a like result. It may,
therefore, be considered certain that some larvæ will bear to be frozen
into solid masses, so that they will snap asunder like an icicle, and
yet return to life again; and even go through all their stages of
development, into the perfect insect. How remarkable a fact this is,
when we remember the deadly effect of frost upon man and the higher
animals!

Many larvæ, however, form nests of various kinds, in which they
comfortably spend the dreary days and nights of this stern season.
"With this view," write the excellent observers, Kirby and Spence,
"the larva of _Cossus ligniperda_ forms a covering of pieces of wood,
lined with fine silk; those of some other moths excavate, under a
stone, a cavity exactly the size of their bodies, to which they give
all round a coating of silk; and the larvæ of _Pieris Cratægi_ enclose
themselves, in autumn, in cases of the same material, and thus pass the
cold season, in small societies of from two to twelve, under a common
covering formed of leaves. Bonnet mentions a trait of the cleanliness
of these insects, which is almost ludicrous. He observed in one of
these nests a sort of sack, containing nothing but grains of excrement;
and a friend assured him that he had seen one of these caterpillars
partly protrude itself out of the case, the hind feet first, to eject
a similar grain; so that it would seem the society have on their
establishment a scavenger, whose business it is to sweep the streets,
and convey the rejected matters to one grand repository. This, however
singular, is rendered not improbable, from the fact that beavers dig,
in their habitations, holes solely destined for a like purpose, as do
also badgers."

A singular variety of larva-nest is mentioned by a Mexican traveller.
He says,--"After having ascended for about an hour, we came to the
region of oaks, and other majestically tall trees, the names of which I
could not learn. Suspended from their stately branches were innumerable
nests, enclosed, apparently, in white paper bags, in the manner of
bunches of grapes in England, to preserve them from birds and flies.
I had the curiosity to examine one of them, which I found to contain
numberless caterpillars. The texture is so strong that it is not easily
torn; and the interior contained a quantity of green leaves to support
the numerous progeny within."

The larvæ of some Australian insects form the most curious nests
we have ever beheld. A representation, taken from specimens in the
entomological collection at the British Museum, will show what
extraordinary structures these are. They appear like minute bundles of
faggots, and have been formed by the insect cutting short pieces of
twigs, all nearly of the same size, and then cementing them together in
the manner represented. Some of these are of a large size, as large as
a moderate-sized pear; others are smaller, and these present the most
beautifully regular appearance, consisting of a number of very small
rods, bound together in a cylindrical form, like the _fasces_ of the
Roman soldiery.

[Illustration: _Australian Larva-cases._]

In this manner larvæ pass through the winter. Without a doubt many
perish; but there remain infinite numbers at the end of this season,
which, from the depths of their cells, become sensible to the influence
of spring, so soon as the first footsteps of that season are felt upon
the earth. The larva wakens to active life once more; and with an
appetite rendered all the keener by its fast of four or five months,
it leaves its dormitory, and begins to consume whatever suitable food
may lie in its way; and so it continues, until the time of its change
approaches.




CHAPTER VI.

PREPARATION FOR A CHANGE.


The last stage of the larva's history hastens on. Its career of
activity and voracity is nearly ended, and the insect's days in this
form are well nigh spent. Hitherto it has been an earthly, earth-loving
being, without either the desire or the power to raise itself into
the airy element, in which multitudes of its species are disporting
the day long. If we may so speak, its highest desires have only been
confined to the quality and quantity of its food; possessing these, it
was content. But now, its hours of feasting are come to a close, and it
has to make ready for a great and momentous change. The crawling, and,
perhaps, repulsive creature which we turn from without regret, has a
high destiny to accomplish, when the period of its sojourn in its vile
body is fully accomplished; and then, that form which now creeps among
the dust of the world, shall mount up as on eagles' wings, and be
carried whither it will through the pure regions of the sky.

The age to which the larva generally attains before this change takes
place is exceedingly variable. To some it is permitted to reach the
venerable age of four or five years; others, three; and many, not
nearly so much. The dung and fungus-feeding insects, as if hastened
forward by the warmth of their position, are at the end of their larva
life in a week; others live a fortnight in this state; and others,
several months. We are told of a curious anecdote of a beetle which had
existed in a desk, set up in an office in London, for upwards of twenty
years, half of which period, according to Messrs. Kirby and Spence,
it must have lived as a larva. But this is quite an exception to the
general rule.

For some days before, the larva loses its long distinguishing
characteristic--its appetite--and now forsakes the plants upon which
it formerly fed; or if it does not forsake them, no longer consumes
any part of them. It becomes, apparently, in some degree sensible
that it is approaching the most dangerous period of the history of
the insect--the state of sleep or torpor in which it is to exist as a
pupa--of which we shall speak more particularly in our next chapter.
Before, although a weak and comparatively a defenceless creature, it
was still able to exercise a vigilant watch against its enemies, and
thus to avoid them, or to prepare for their reception; but now, its
eyes are to be closed in a death-like slumber; its body to hang a
tempting bait to any wandering foe, or hungry bird, and it can in no
way resist the attacks of the feeblest adversary.

As if fully aware of this, the wonderful instinct of the larva meets
the difficulty by teaching it to select the best place for its
concealment from a dangerous notice. With this view, it sets out in
search of a hiding-place, and rests not until it has obtained a city
of refuge which may prove to it a defence against the enemy. It may be
some little recess, covered by an irregular stone, and sheltered round
the sides by moss and the upspringing grass; or, perhaps, a little hole
in the earth has received the poor fugitive from future harm, and in
order to conceal itself more completely, it has drawn over the mouth
of the cave a covering of leaves. Here, safe from observation, the
larva bids a farewell--to speak as the poets speak--to the busy staring
world for awhile, and loses all recollection of its past history, in
the night of torpidity upon which it has now entered. The larvæ of the
lady-bird, and other insects, glue themselves fast to the under side of
a twig or leaf, and here pass the days of their sleep in safety. Many
of the larvæ of insects whose life, up to this period, has been passed
beneath the surface of some glassy pool, now quit the pure element,
and seek the shore, on which they are to pass the remaining portion of
their existence.

But there are two other ways in which larvæ prepare for the state
of _pupa_, which are so curious, and prevail to such a large extent
among insects, that we may be excused for following the example of
all authors upon insect history, and treating our readers to the
interesting facts which have been recorded by various observers upon
this subject. One of these is the plan of hanging themselves up in
the air, like sailors in their hammocks; and in other positions, this
plan is commonly called the _suspension_ of the larva. The other is
the formation of beautiful cases of various kinds, which are called
_cocoons_, in which they wrap themselves up close during the period to
be devoted to the pupa state. Let us speak of these each separately;
and, first, of the case, or _cocoon_, as a place of concealment for the
larva. It is right, however, to premise, that, while the greater number
of insects are in a torpid or half-torpid state while in the pupa form,
all are not so, as will be noticed in the next chapter; and those which
are not do not of course require the protection of a cocoon, or the
contrivance of a silken hammock.

The material of which the case or cocoon is composed is a beautiful
silken fibre, which is furnished by a spinning apparatus placed either
at the extremity of the body, or more frequently at the mouth of
the insect, whence it proceeds in a filament of the utmost delicacy
and transparency, but at the same time of considerable tenacity. By
its means alone cocoons, of a number of different kinds, some of
extraordinary beauty and ingenuity, are constructed; but in other
cases the insect has recourse to various materials to assist in giving
strength to the walls of its cell.

[Illustration: _Cocoon of Silk-worm._]

The best example, and the most familiar one we can select of a purely
silken cocoon, is that of those

              "----spinning worms
    That in their green shops weave the smooth-haired silk."

This beautiful and valuable cocoon, when examined externally, appears
to be formed in two different ways; for the outer covering is loose and
open, while the inner one is compact and close, and so in truth it is,
although both coverings are formed of a single thread. The outer has
been called the _scaffolding_, by means of which the inner and more
solid covering is constructed. The larva stationing itself between two
leaves, or in any other suitable spot, fastens its thread to one of the
adjoining surfaces, and then proceeds to draw out the fibre and fasten
it in various positions until it has woven around itself an envelope,
as it were, of loose gauze. After this has been done it begins to form
the closer and more compact structure of the inner envelope, laying
on the silk backwards and forwards in a series of zig-zags, until it
has laid on several layers, and thus completely shut itself in. The
loose outer portion forms what ladies so well know under the title of
flos-silk; the inner fibres are the most continuous, admitting of being
wound off without breaking, and they form the ordinary silk of commerce.

[Illustration: _The Larva surrounded by its Palisade._]

M. Lyonnet has given a most interesting account of the proceedings of
another larva which far surpasses the silk-worm in the ingenuity of its
manner of forming the cocoon. This larva is very small; in fact, not
more than the sixth of an inch in length, and is found on the under
side of oak-leaves. M. Lyonnet observes, that beyond all the larvæ he
had ever watched, he considered this creature the most inconceivably
ingenious workman. Its little cocoon is of a white colour, and of a
long oval form, having its upper surface ornamented with seven upright
ridges. The first thing the creature begins by doing, is to erect,
in the most curious manner, a series of little upright palisades of
silk at a certain distance from each other, all round its body, so
as to form a sort of oval fence, and probably the larva intends them
to serve as a sort of hedge to keep off intruders while it is busy
at work! After spinning half its case, it turns round, and begins at
the opposite end, and thus forms the other half; it then unites it
in the middle, and by so doing incloses itself in a very pretty cage
of silken net-work, which it subsequently strengthens by adding a
firm layer on the inside. The time taken in the construction of this
ingenious cocoon is not more than half-an-hour. It is quite impossible
to understand how the little being contrives to form the upright ridges
on the surface of its cocoon; and as the larva is so minute it is
almost hopeless to expect to discover it. Attempts have been made to
unravel the difficulty, but not with complete success. When, looking at
some magnificent works of man, we are tempted to become inflated with
pride, let the remembrance of what this tiny insect can do keep us
humble, and direct our admiration rather to Him who is the Author of
all wisdom, the Giver of every good and perfect gift.

Upon the leaves of pear trees we may sometimes find a pretty cocoon of
very slight and elegant texture, formed of silk, as shown in the cut.

[Illustration: _Cocoon on a Pear-leaf._]

A very singular cocoon is spun by the larva of a common moth, somewhat
of the outline of a balloon in form. This cocoon is spun in a very
slight manner, and thus offers a striking contrast to those of many
other insects; in fact, it is so slight, and the meshes are so open,
that the insect can be readily seen within suspended in a hammock of
silk, and thus presenting a very curious appearance. In another, the
inclosed insect looks just like a poor prisoner within a grating.

[Illustration: _Cases formed of Epidermis of Bark._]

In order to give a sufficient degree of strength to their cocoons,
some larvæ adopt the plan of forming them partly of silken fibre and
partly of other materials. Réaumur, being on an entomological excursion
in the forest of Vincennes on a fine day in the month of May, fell in
with a most curious cocoon, formed by a larva which feeds upon the
oak-tree. At first he could scarcely conceive what the object he saw
before him was, but on removing the branch it proved to be a very
singular cocoon. Detaching a small branch, on which was a larva just
commencing its cocoon, Réaumur, finding the evening draw on, set out
on his return home. The larva did not seem to discover the fact of its
being carried away a prisoner; and as the entomologist carried the
branch with gentleness, it proceeded with its task as comfortably as
if stationed on the tree it was now leaving behind. Réaumur beguiled
the tedium of the way by carefully watching its mode of proceeding in
the formation of its cocoon. He thus noticed the larva cutting very
delicate layers of the fine upper skin or _epidermis_ of the bark of
the twig, which it fastened together by silken cords, and then formed
into two wing-like pieces fastened on each side of the twig in the
manner represented in the cut, something like the feathers of an arrow
in appearance. And now, this being done, the difficulty was to draw
the two sides together, and so to convert them into a covering for
its body. The manner in which this was done will hardly, perhaps, be
imagined. It will be best understood if the reader will cut out two
pieces of paper of the shape of these two side portions, fasten them on
with a little glue by one of their edges to a piece of twig, and then,
by a fine needle and thread, draw them together by stitching from side
to side all the way up. The larva does something very like this, for it
fixes silk cords to each of the outer edges, and then pulls and hauls
with all its might until it has forcibly bent over the layers until
they meet, and then it ties the edges together by short cords, so as
to produce a seam so beautifully close, even, and fine, as would put
the "fine-drawing" of the most superlative tailor to shame; in fact,
the join is frequently quite imperceptible. Having done this, it lines
the inside with beautiful tapestry of silk. By the time Réaumur and his
friends had got to the end of their walk, which occupied an hour and
a little more, the larva had, after vast labour, joined together its
seams, and far advanced toward the completion of its task.

[Illustration]

Réaumur made also some most interesting observations upon a larva which
constructs its cocoon of a sort of silken mesh, the interstices of
which are filled with grains of earth. Having broken off the top of
a cocoon he witnessed the singular spectacle of the larva proceeding
to mend it again. Without leaving its cell, the patient labourer put
its head out of the opening in the attitude represented in the cut,
and, after looking about for a little time, picked up, one by one,
a number of grains of earth, which it stored up in its case. After
this, it filled up the sides of the opening with a net-work of silk,
working the grains of earth into it as it proceeded. For three hours
the larva worked incessantly at its task, and at the end of that time
had materially reduced the size of the opening. Réaumur was now curious
to observe how the opening still left would be filled up, as the insect
could no longer put its head out, and he expected to see it filled up
with a mesh of silk. But he had not given the larva due credit for
ingenuity in making this supposition. It filled up the opening first,
with a mesh of silk, but between the meshes, in a most curious manner,
it thrust out some little grains of earth, which it had previously
stored up, until they actually appeared on the outside, and any one
would have supposed they had been laid on from without. It finally
ended its labours by coating the inside of the opening also with a
layer of earth. Réaumur afterwards cut the cocoon in half with a knife,
and by that means was enabled to see how successfully the larva had
repaired the injury.

We must now speak briefly of the Suspension of the Larva; and it may
be mentioned, that the insects, whose larvæ perform this manoeuvre,
are almost exclusively the butterfly tribe. There are various ways of
effecting this object. The spinning apparatus, by which the cords are
to be formed to sustain the body of the insect in the air, is situated
in the _mouth_ of the larva, and it may well be imagined that the
insect, which is about to hang itself up by the _tail_, has no easy
task to perform in having to fasten its cords to the tail, and then to
the branch above it. If a spider wished to hang itself up by the tail
it would be a very easy thing so to do, for the spinning apparatus is
placed there, and it has only to let itself fall from a branch after
first glueing the end of the cord to it; but a larva is differently
circumstanced, and it requires no slight display of ingenuity to
accomplish its purpose.

Its first process is to select a suitable leaf or twig, upon which it
weaves a sort of little mound of silk of the shape of a button. This
done, it examines it carefully to ascertain its strength, and satisfied
therewith, it then proceeds to thrust its two hind legs in amongst the
threads of which the button is composed, and in so doing it causes
the hook-like processes which fringe these legs to become securely
entangled in them. It then is safe as to the issue, and now lets its
body drop down, fearless of the most violent rockings to which even a
tempest might expose it.

Another way of suspending themselves is almost equally singular with
this. It may be witnessed by the reader if he will take the pains to
collect the larvæ of the common white butterfly, found in abundance
upon our cabbage rows; and by properly attending to, feeding and
watching them, this curious proceeding may generally be observed, in
a few at least of the number, supposing that the others may have hung
themselves up without being seen in the very act. If we were to set
a mountebank to the task this larva has to perform, it may well be
doubted whether with the richest reward before him he could manage to
effect it. First, he would have to tie both his feet fast to a branch,
so that he would swing head downwards; then, in order to hang himself
in the horizontal posture, he must bend his body up, fasten a cord
round the branch in a proper place, so as to form a loop, and then put
his head and body into it, so that it would support him comfortably
just under the arms. Probably the most supple-jointed gentleman would
find himself discomfited in the attempt. The caterpillar in question,
however, does all this, and more; for it has _to spin the ropes_ with
which it is to be suspended. Fixing its hinder part, in the manner
just described, to the little button of silk, which it first forms, it
then spins the girth, in which it intends to trust its safety, by the
apparatus of the mouth. Sometimes larvæ tie themselves in an upright
position, as martyrs to a post; but the most common method is the
horizontal one, giving the insect the resemblance of a sailor swinging
in his hammock.

[Illustration: _Horizontal Suspension._]

[Illustration: _Perpendicular Suspension._]

We must ask attention, before we close our chapter, to one more
account of the proceedings of a larva; and this too is in a common
insect--perhaps the housewife would say a little _too_ common--the
_meat-fly_. This larva, when its days in that condition are at their
close, quits its long greedily-devoured and disgusting food, and
penetrates into the earth; there it contracts its body in a singular
manner, and its skin becomes thickened and hard, so as to form a sort
of parchment-like case, _inside_ which its jaws are cast off, instead
of outside, as is commonly the rule. "Were such an extraordinary
transformation as this to happen to one of the larger animals, it would
be held forth as altogether miraculous," writes Mr. Rennie. "Were
a lion or an elephant, for example, to coil itself up into a ball,
compressing its skin into twice the thickness and half the extent,
while it remained uniform in shape and without joinings or openings:
and at the same time were it entirely to separate its whole body from
this skin, lie within it, as a kernel does in a nut, or a chick in an
egg, throwing off its now useless tusks into a corner; and then, after
a space, should it acquire wings, break through its envelope, and take
its flight through the air, there would be no bounds to our admiration.
Yet the very same circumstances in miniature take place every day
during summer, almost under the eye of every individual, in the case
of a blow-fly, without attracting the attention of one person in a
million." So much more are we attracted by great things than by small.

The work of preparation finished, the insect securely buried in its
cell or warmly surrounded by its cocoon, or hanging up to the branch
of a tree, or in any other way concealed from view or protected from
injury, little more remains to be added to the larva history. Its last
action, after settling itself in a comfortable position, is to cast off
its skin, which is generally, in the case of those larvæ which inhabit
cells or cocoons, left inside the recess: sometimes it is cast out. The
period at which the insect ceases to belong to the larva stage, and
passes into the next, varies, and will receive notice in the following
chapter.

When in the vengeance of God upon the guilty land of Egypt it
pleased Him to send the plague of insects, the exclamation of the
magicians was: This is the finger of God." Such, in an admiring
sense, may be ours also as we look back upon what we perceive God to
have done for this humble portion of His creation in the few past
pages. What provision, what wonderful forethought and wisdom has
not been exercised upon beings which man despises, or even abhors,
and which fall daily by thousands under foot, crushed and forgotten
except by a few. Let us search the green lanes and hedge-rows more
assiduously,--let us poke even into the dirtiest corners,--let us
examine well the leaves and branches in our gardens, the depths of
the purling brook, the cavities of the aged trunks, and the cracks in
the deep-furrowed bark,--let us look narrowly upon the cabbages and
nettles, as well as upon the rose-bush and myrtle,--let no place, in a
word, be beneath our scrutiny, no object beneath our notice;--let us
do this, and we shall not need to sigh after foreign scenes, or the
majestic wonders of nature, for we shall have a microcosm, a world of
wonders, in a table drawer, and an exhaustless theme of admiration in
the contents of a tumbler of water.

[Illustration: INSECTS ESCAPING FROM THE PUPA CONDITION.

Page 300.]




PART III.--THE PUPA.




CHAPTER I.

THE TRANSFORMATION.


Hanging to the slender branch of yonder rose-tree, swinging to and
fro with the gentle air which blows in scented waves through the
flower-garden, is a little object to which we wish to direct attention.
Had not notice been thus directed to it, in all probability we should
have passed it by, if we observed it at all, only considering it to be
a broken twig or withered leaf suspended by a cob-web. We may examine
it minutely, but all is quiet and motionless in the little mass, and it
is impossible to detect the least sign of life. A casual eye would rest
upon it without interest, and would turn away from it uninstructed as
to its nature and properties. In colour it has nothing to attract--it
is of a dirty white or brown, and in shape it is, though curious, so
small, and so uninviting, that few would take the trouble to pay much
attention to it. Day by day it swings from its silken cord, and is to
all appearance an object without interest to all around it.

Yet this slumbering, unattractive mass contains a living being. Though
the aspect of death has passed upon it, and though we may perhaps be
unable to detect the symptoms of movement in its parts, it is yet
alive, and the lapse of a little time will convert the slumbering
being, thus singularly hung up to be the sport of the wind and rain,
into a creature more extraordinarily active than perhaps any other in
the animal creation. While it sleeps, great changes are taking place;
it is receiving new organs, it is being matured, developed, perfected,
fitted for a nobler existence, and for a higher range of duties, than
it has yet known. Such is the _pupa_.

From these remarks it will be sufficiently evident that this chapter
of our insect history has to speak of a period when there are but
few traces of active existence in the insect, and it might therefore
be supposed there remained little to be said upon a period of the
insect's life which is only comparable to a prolonged sleep. But
entomological science is too rich in interesting matters upon every
subject to admit this conclusion, and we shall find that there is much
to be narrated which equally, with what has formerly been written, is
calculated to raise our admiration to the Great and Beneficent Author
of all Nature.

If we turn to a Latin Dictionary and hunt out the word which stands at
the head of this chapter, _Pupa_, we shall find several definitions of
it given; for example, _a little girl_, _a doll_, and _a baby_. What
have either of these to do with an insect? some will exclaim, and they
may feel disposed to consider the great Linnæus, who gave the insect
tribes while in this stage this title, to have been not over happy in
his selection of terms. But those who thus exclaim have perhaps only
seen _babies_ as they are clothed in England, possessing the power and
comfort of free movement, and having their arms and legs at liberty.
Between the aspect of these little creatures and our insects no one
can trace any resemblance. But it is very different on the continent;
there, out of the strange notion that it will keep the poor little
being's limbs straight, it is the custom to wrap babies up in swaddling
clothes, until they can neither stir hand nor foot, and they are made
to resemble Egyptian mummies as nearly as possible. Babies wrapped
up in this cruel and barbarous manner form objects of so peculiar an
appearance, that it is quite ludicrous to trace the resemblance between
them and the _pupæ_ of insects; and therefore Linnæus, as it appears,
could scarcely have selected a better epithet for the insect than its
present title of _pupa_, as it too has the aspect of being wrapped up
in swaddling bands.

[Illustration: _A Pupa._]

But, as we formerly mentioned with regard to larvæ, all insects in the
_pupa_ state are not called popularly by their scientific and correct
name. Those that are closely wrapped up, and are in fact complete mummy
insects, are called sometimes by the term _Chrysalis_, or _Aurelia_,
because they are sometimes of a _golden_ lustre, the one being derived
from the Latin, the other from the Greek term for "gold," and this
even when they are not gilded in this manner. Again, when, as we shall
presently have to notice, the insect in the _pupa_ state is still
capable of eating or moving, or when it does not lose its legs, its
popular name is a _Nymph_. As in the preceding chapter, so in this, we
shall not regard these terms, as they only create a great amount of
confusion, but shall adopt the true term, _pupa_, throughout, whether
the insect spoken of falls within the one or other of these popular
divisions, or not.

We traced the larva in the last chapter up to that period in its
history when it enters its cell, or otherwise retires to concealment,
previous to its becoming transformed into the _pupa_. Here, immured in
darkness, and alone, it is left to undergo that mysterious struggle of
the vital powers which is to end in producing a new and more perfect
creature out of one which, however perfectly adapted to its condition,
is very far inferior, as regards the completion of its organization,
to that which it is destined to become; and here we may appropriately
pause to take up the history of the curious larva so recently
described, at p. 207, as performing the feat of hanging itself up by
the tail from cords spun by its mouth; since it exhibits to us in a
striking point of view the shaking off of the old form of larva, and
the putting on of the new one of pupa. In addition to this, it is,
perhaps, one of the most astonishing instances of animal agility with
which we are acquainted.

In order to make its manoeuvres and the difficulty of them the more
easily comprehended, let us (to follow Messrs. Kirby and Spence in
the same matter) put a case of a somewhat similar kind before the
readers by way of supposition. Country fellows at wakes and fairs
frequently--for the diversion of the company there assembled, or for a
prize of some value in their estimation, perhaps a fat pig, or a leg of
mutton--run races in sacks which are tied close about their necks, and
of course tumble about a good deal, and display anything but a graceful
mode of progression. "Now," say these authors, "take one of the most
active and adroit of these, bind him hand and foot, suspend him by the
bottom of his sack, with his head downwards, to the branch of a lofty
tree; make an opening in one side of the sack, and set him to extricate
himself from it, to detach it from its hold, and suspend himself by
his feet in its place. Though endowed with the suppleness of an Indian
juggler, and promised his sack full of gold for a reward, you would
set him an absolute impossibility; yet this is what our caterpillars,
instructed by a Beneficent Creator, easily perform!"

[Illustration: _This Cut shows the entire change from the first rupture
of the skin to the casting away of the old skin._]

[Illustration: _Tail of a Pupa magnified to show the toothed parts._]

Let us proceed to show in what manner the caterpillar performs this
wondrous feat. After suspending itself in the way already described,
a little time generally elapses, during which the insect by turns
contracts itself, and then dilates again. At length its skin splits
near its head, and a portion of the pupa appears, which acts like a
wedge, and, being thrust partly through the slit, causes it to tear
still higher and higher towards the tail. The insect continues its
painful labours, swelling and contracting alternately, so as to push
the torn skin higher and higher up, as one would roll off a stocking,
until at length the old skin is folded into several rolls, and is quite
at the tail. But the task is as yet only half accomplished; the most
arduous and difficult part remains to be done. The pupa is shorter than
the larva, and consequently hangs out of reach of the silken button in
which the latter was firmly fixed by its hind legs. It seems now as
if the poor insect must fall, for there appears no way for it to get
up to the silk anchorage, and the folds of the pushed-up old skin are
all that retain it in its position, which, as may be imagined, is far
from a secure kind of fastening. How is it to disengage itself from its
case, and be suspended in the air while it climbs up to take its place?
Without arms or legs to support itself, the anxious spectator expects
to see it fall to the earth. His fears, however, are groundless; the
supple segments of the pupa's abdomen serve in the place of arms.
Between two of these, as with a pair of pincers, it seizes on a portion
of the skin; and, bending its body once more, entirely extricates
its tail from it. It is now wholly out of the skin, against one side
of which it is supported, but yet at some distance from the leaf;
the next step it must take is, to climb up to the required height.
For this purpose it repeats the same ingenious manoeuvre: making
its cast skin serve as a sort of ladder, it successively, with its
different segments, seizes a higher and a higher portion, until in the
end it reaches the summit, where with its tail it feels for the silken
threads that are to support it. The tail is provided with a number of
minute hooks which catch in the meshes of the silken button, and the
pupa, thrusting it into the meshes of this button, feels quite secure
as to the result, and drops safely into the perpendicular position,
dangling in the air as gaily as did the larva before it. But its old
skin still clings to it, and seems greatly to annoy it by its presence;
so much so, that it sets about attempting to cast it down altogether.
As it will be remembered that the legs of this skin are still firmly
attached to the silk, in consequence of their hook-like form, it will
be evident, that this also is a task of some arduousness. In order to
get rid of it, it jerks itself about in various directions, and spins
round very rapidly,--doubtless the reader has often seen the insect in
this act, and has wondered what was its object in whirling round after
this manner,--by this means at length the cast-skin appears loosed
from its hold and drops off. The whole proceeding from first to last
is represented in our engraving. The little hooks of the tail of the
pupa are represented in the adjoining cut much enlarged. Well does
Réaumur exclaim,--"These manoeuvres of withdrawing its tail from the
old skin, of climbing up the old skin, and of hooking its tail in the
silken button,"--and, as we might add, of whirling itself, and in other
ways agitating itself to get rid of its old skin,--"are manoeuvres
so delicate and perilous, that we cannot help wondering how an insect
which only executes them once in its life, should execute them so
well; and we are led to the inevitable conclusion that it has been thus
taught by a Great and All-wise Master."

The manner in which other larvæ cast their skins and become pupæ when
they enter their cell cannot be described, as they perform this act
in all the privacy and darkness of their solitary habitations; but in
all probability it differs in no respect from the manner in which the
same creatures cast their skins when they moult, excepting that the new
being which emerges from the cast-skin is no longer a larva, but a pupa.

The time occupied by the creature in its process of change differs
in different species. In some it is short, in others it is long.
Generally, it does not exceed a few days. We are told, however, of the
larva of some insects which are six months before they become pupæ. The
Baron de Geer tells us with surprise of the larva of a moth which he
had watched. It became a larva, and spun its cocoon, in the month of
August, 1746, and was attentively kept during the winter. The spring
came, but the larva still remained a larva, and did not show any signs
of changing its form; and winter came again, finding it still a larva:
the second winter passed, and it was not until April 1748, that is,
more than eighteen months after it first became a larva, and entered
its cocoon, that it underwent the change, and became a pupa: some time
afterwards it became a perfect insect.




CHAPTER II.

WHAT IS A PUPA?


But it may now be asked, What is a pupa, and what are the differences
between it and a larva, and between it and the perfect insect? It is
very necessary that this should be clearly understood; and to that end
we shall endeavour to render our explanation as simple as possible.
But it will be far better than the best description, if the reader
will be persuaded to watch these changes throughout himself. The
butterfly tribe furnish the very best illustrations in the world; and
by merely collecting a few caterpillars from the way-side, or from
the kitchen-garden, a source of amusement will be opened which will a
thousand-fold repay the trouble and time consumed in the occupation.
Of all other ways, personal observation, when it is so readily to
be effected as in the case of these insects, is the best and most
impressive method of becoming acquainted with the "Life of an Insect."
Such knowledge is far more entertaining than book-knowledge, and is
much more agreeable to acquire, and more easy to retain.

We must guard our definition of what a pupa is, by reminding the reader
that some insects with which he is very familiar do not pass through
this change in the same manner that the majority of insects do; that
is, in a state of torpor or sleep. If he were to rear up a spider from
the egg, and were to watch for the time when it would become a still,
lifeless-looking object, like that which we have called a pupa, he
would assuredly be disappointed, and he might accuse this little work
of leading him into error, because it declares that all insects must
pass through the pupa state before they become perfect in their form
and number of their parts. Yet that very spider has passed through
both the larva and the pupa state under the observer's eye without his
being able to recognise the fact, simply because in both these states
it is very like the perfect insect, and can walk about and eat just
as usual. In fact, it is more than probable that spiders of the same
kind in these different conditions could scarcely be recognised so
as to say that they were pupæ, or perfect insects, even by tolerable
entomologists; and it is very likely that mistakes of this kind have
often occurred.[I] We learn, therefore, from this statement, that some
pupæ are active, and move about just as they did before, although they
_are_ in the pupa state.

In a great number of cases, then, a pupa is a state in an insect's life
when it rests from active exertion, and from taking food, and when,
underneath the dry and withered skin, a series of great changes are
taking place, which are preparing it for its future life in the perfect
state. Thus it differs from the _larva_ state in not eating and moving,
and in the important particular,--that it is receiving new parts and
organs, which are added to it under the skin. It also differs from the
_perfect insect_ in the same respects as in the first place from the
larva, and also in the important circumstance, that the perfect insect
the moment it enters that state, has no more organs added to it--it
is, in fact, perfect, while the pupa is imperfect. Let us place these
differences in a tabular form:--

  The Larva              The Pupa                   The Perfect Insect

  Moves about and eats.  Does not move about        Moves about and eats.
                         nor eat.
  Has no new organs                                 Has no new organs
  added to it beyond     Has several new organs     added to it, beyond
  those acquired in the  added to it, to prepare    those obtained in
  egg.                   it for the perfect state.  the pupa state.

Let us repeat our caution, that this definition is only applicable
to _inactive_ pupæ. In the active pupæ the same development of new
organs takes place, but it does not interfere with the usual actions
of life. We must also add, that some of the pupæ which we must call
inactive, nevertheless are not wholly without motion, but are capable
of manifesting that life is in them, death-like though they appear,
by slightly moving the lower part of the body.[J] All inactive pupæ,
however, are without the power of moving about.

At the risk of being thought tedious, it has been indispensably
necessary to be thus precise upon this point; a little careful study of
these two or three pages will fix the distinctive characters of the
pupa firmly in the reader's memory, and will enable him to find the
account given of its history clear, easy, and interesting.

Having thus defined what the pupa state is, let us take up one of these
withered objects, and by a little gentle treatment, with the assistance
of a delicate scissors, a sharp pointed penknife of very keen edge,
and two or three pins, we shall succeed in unrolling the insect mummy.
In order to obtain the best sight of what the pupa case contains, it
will be advisable to select as large a pupa as can be procured. Those
of the butterfly tribe are well suited for this purpose. If we are
pretty fortunate in our dissections, we shall succeed in discovering,
that within the membrane-like skin there is exhibited a beautiful
spectacle of order and neatness. The legs, and wings, and other
external appendages, are folded down close to the body of the insect.
The feet are often crossed smoothly over the breast, and the wings are
flattened against the side of the body; the antennæ are also neatly
arranged parallel with the legs; and altogether the insect presents a
very singular appearance, from the fact of all its organs being thus
smoothed down, compressed into the smallest compass, and enveloped
by the external skin. The mummy appearance is very striking in some
pupæ, as in the specimen figured. The appearance of the folded limbs
is indistinctly exhibited in the companion pupa. All the parts of the
perfect insect can be distinctly traced, if the pupa is sufficiently
matured.

[Illustration: _Pupæ._]

By gently using a fine needle, the wings, antennæ, and legs, can be
separated from the side of the body, and made to exhibit somewhat of
their natural appearance; but as yet every part is widely different
from the corresponding parts in the perfect being. The legs are
shapeless, the antennæ are imperfect, and the wings,--those glorious
organs of the complete condition,--are as yet devoid of their splendid
tints, being of a greyish colour, and exhibiting little resemblance to
the elegant form afterwards to distinguish them.

Strange to say, every organ in this pupa is enclosed in a sheath of
membrane. The head of the insect is covered by a case; the delicate
antennæ, however long or fine, have their cases, or sheaths; even the
eyes are provided with them. They exist also upon the trunk, wings, and
legs, and _tongue_, or proboscis. These cases must not be mistaken for
the general outer case which covers the whole insect; they are separate
from that, and cover the organs in question closely, after the manner
of a glove.

If we were to open a pupa within a few hours after it had assumed this
state, we should find its interior filled with a milky fluid, in the
midst of which its future limbs and organs are seen very distinctly,
but are as yet in a most fragile, or even half fluid state. At a little
later period this fluid disappears, and hardens into a sort of glue,
which partly fastens down the tender limbs into their proper position
until the appointed time comes for the insect to burst from its sleep
and live, and from which the case which covers them is formed. From
the account thus given of the contents of the pupa-case, it will be
apparent that the pupa possesses, when perfect, all the organs of the
complete insect, head, eyes, antennæ, wings, legs, &c., and is in fact
only different from it in that it is still inactive to a great extent,
and still a prisoner within its cell of membrane. In a little while
the bonds which keep it in the tomb will be broken, and the slumberer
shall rise a glorious creature to the enjoyment of all the happiness of
a new condition of existence.

[Illustration]

Perhaps few things would cause a person ignorant of insect life more
amazement than if we were to hold before his eyes some of the varieties
of pupæ in one hand, and the perfect insect in the other, and were
then seriously to assure him that both were the same creatures in
reality. "Can it be possible?" he might exclaim. "This dry, brown
little mass, with these singular knobs, and this elegant insect with
its gaudy wings and delicate figure--these the same being!" Nor when
we look at the various figures of pupæ, should we be much surprised at
his exclamation. In one of the cases at the British Museum is a very
large pupa which we have had engraved, and which is here presented to
the reader. In this curious creature the folding up of the limbs is
very obvious; and some idea of its strange aspect may be formed from
the representation of it here given. The pupæ of several moths are
very singular in shape. In some there is a sort of little hook, which
sticks out from the head, and seems as if it were intended to hang up
the creature by. In others there is a kind of nose attached to the
head, giving it a droll appearance. The cause of these protuberances is
the long tongue of these moths, which, as it is much longer than their
bodies, could not of course be contained in the pupa case, unless it
was folded up; it is, therefore, neatly folded up and packed into these
receptacles, where it is stowed away until, by the insect awakening
to active life, this singular instrument becomes necessary to them,
when it is withdrawn. The older naturalists, who loved to find out
mimicries of all kinds in nature, used to be fond of painting pupæ
with human faces, on account of the frequent resemblance to a Roman
nose which is found among them. Goedart, a celebrated naturalist, has
drawn several, which we are sure will excite the merriment of our
readers, and we have therefore shown these remarkable creatures _as
represented by him_ in the adjoining cut. One is a respectable-looking
old gentleman's face, with his hair brushed up very primly off his
forehead. Another resembles a mermaid, for it has the head of a lady,
and something like a cap, but its tail is more like that of a fish.
The others are quite caricatures. It is the introduction of a dot, to
represent the eye, which gives the resemblance to the face in these
figures; without it they are by no means strikingly like the face.
Madame Merian has favoured us also with some very curious drawings of
pupæ of the insects of Surinam, which appear more natural than those of
the last author, and present a very fantastic aspect, by reason of the
curious projections which stick out from their heads. A few of these
are represented below.

[Illustration: _Pupæ after Goedart._]

[Illustration: _Curious Pupæ. From Madame Merian's work on the Insects
of Surinam._]

As in the case of the larva, so with the pupa; if it is found in a
dark situation, it will probably be destitute of colour, or, at any
rate, it will only be of a yellowish white: such pupæ, when taken out
of their natural hiding-place, and exposed to the sunlight, become of
a dark colour. Indeed the majority of pupæ are without any of the gay
colouring which distinguishes the previous condition of the insect.
It seems as if it had been thought unnecessary to deck in gorgeous
raiment the cerements of what we might call "the tomb" of the insect.
But there are some beautiful exceptions to this rule. The pupæ of
most butterflies, which are suspended in open day, are of a green or
yellowish brown colour. Some, however, are painted in fairer colours;
and a still greater number are speckled with glittering spots of
golden hue, and shine as though gilded with the purest leaves of that
precious metal, and burnished. Hence, as before explained, the Latin
and Greek terms of _aurelia_ and _chrysalis_ for the pupæ of these
insects. The gilding makes them very attractive objects, being applied
now in streaks, now in spots, and occasionally,--and this in the very
common pupa of the butterfly whose caterpillar, or larva, feeds on the
nettle,--they are entirely covered with this splendid coat. The shade
of gilding ranges in the depth of its tone from a very pale yellow
to the full lustre of virgin gold. No wonder that those who mistook
the object of chemistry, in trying to turn all things into gold, were
attracted by these glittering things, and actually believed these
spots to be of real gold, and hence imagined that they had found out
an argument in nature for the transmutation of common metals into that
coveted one. But a little experiment, which it is in the power of any
one to perform, would soon have undeceived them, and taught them the
truth of the proverb, "All is not gold that glitters." By infusing a
portion of saffron in hot water, and straining it off after a little
time, and adding to the rich yellow liquor thus obtained a few lumps
of pure gum Arabic, a sort of gilding varnish will be obtained, which,
if applied to a bright shilling, will give it very much of a golden
appearance, owing to the shining of the metal showing through a
transparent film of a golden colour. The gilded look of the pupa was
found by Réaumur to be produced in the same way by the shining white
membrane of the inner skin showing through the outer skin, which is of
a transparent yellow.

In the Transactions of the Linnæan Society for 1833, the Rev. L.
Guilding describes a very curious pupa, the case of which resembles
pearl. These little bodies are found in abundance in the island
of Antigua, and are often sent home to Europe, under the name of
"ground-pearl," as distinguished from the ordinary fishery-pearl.
They are devoured by turkeys, and fowls, until the birds are nearly
choked with them, when the remedy is to pour vinegar down the throat,
which dissolves the pearls, and sets the poor bird at ease. They are
strung into necklaces and purses by the ladies of the Bahamas. They
long caused much perplexity to naturalists; but they were ultimately
found to be really only the pupæ of a little insect which appears to
infest the ants, those voracious creatures, and thus to keep down their
numbers. A representation of the ground-pearl, and the insect within,
is annexed.

[Illustration: _Ground Pearl. The Insect and its Case magnified._]




CHAPTER III.

RESPIRATION OF THE PUPA.


Having glanced at these particulars in the history of the pupa, we come
to the important question,--Does the pupa, in this torpid condition,
still breathe, as the larva did, or not? On a careful examination we
might detect, with the help of a magnifying glass, the same breathing
holes or _spiracles_, spoken of on page 161, as appertaining to the
larva; and were we sufficiently skilful to dissect the pupa, we should
find much the same arrangement of air-tubes within the body. In the
absence of all other means of ascertaining the fact, we should be
warranted in concluding from the presence of these organs alone, that
the pupa has the faculty of breathing, no less than the larva. M.
Réaumur has given a beautiful description of the breathing-holes, or
spiracles, of the pupa, and has represented them in an engraving, of
which a copy is furnished at page 161. He found that they are protected
by little valve-like contrivances, just as our mouths are protected
by our lips; and these can be opened or closed at pleasure by the
creature; so that if plunged into water, that fluid cannot enter the
insect's body, for all its little doors--and there are no fewer than
eighteen of them!--are fast shut. Singular to say, however, if plunged
into oil, the oil has the power of entering them, and the pupæ may be
thus drowned.

It is very easy to put the fact of the breathing of the pupa, inanimate
as it appears, to a certain test. By taking a wine-glass half full
of water, and putting it under an air-pump, and then exhausting the
air, we shall be able to extract the air which exists dissolved in the
water: or some water that has been boiled and allowed to cool will do
as well. If we now put a pupa into this water, and again exhaust the
air from the receiver, we shall notice, at the second stroke of the
piston, a number of little jets of air come from the insect's body at
the places where the spiracles are situated, thus clearly proving that
the creature breathes air by this apparatus. The fact may be tested
also in another way--and both this and the preceding experiment are
due to the ingenious Réaumur. He took the pupa of a butterfly, and
suspending it by a thread immersed it half way down in oil; on taking
it out after some time it was still alive and apparently uninjured, the
reason being, that the entire number of its breathing-holes were not
covered. He took another of the same species, and plunged it entirely
under the oil, and taking it out after a time it was found to be quite
dead; in fact it had been suffocated by the air being shut out from
its breathing apparatus, and that as effectually as if it had been one
of ourselves lying at the bottom of the sea. We may say, therefore,
with perfect accuracy, that though the pupa, this seemingly un-living
object, neither moves nor eats, nor in any other way gives us a sign
that it is alive, except in a few cases, and that in its advanced
stages, we can, nevertheless, prove it to be living; as it can be shown
that it has the power of breathing; and if it breathes, it lives.

We may take the liberty of appropriately appending to this statement a
most interesting and delightfully-told anecdote, from the pages of the
Baron de Geer, of an insect whose larva lives in the water, but whose
pupa is an air-breathing creature, and consequently would perish if the
change from larva to pupa were to take place under water, without some
especial contrivance to furnish it in the pupa form with a supply of
air. Yet how can this be, when the insect is under water the whole time
up to its becoming a perfect moth? We shall hear:--

"At the commencement of spring, as soon as the frost and ice had
disappeared, I sauntered out one day to procure some fresh plants from
the bottom of a stream, in order to feed some of my caterpillars with
them. Between the leaves of these aquatic plants I presently found a
large number of aquatic larvæ, which had there safely passed through
the rigorous season just gone by. I took a number of them, and put them
in some boxes, where they eat the leaves with which I fed them. There
they grew larger from day to day, although by slow degrees. I tended
them until June in the same year without perceiving any other change
in their appearance than that they had grown to a considerable size.
But at the commencement of this month I noticed that they became very
uneasy; they forsook their leaves, and wandered about the sides of
the boxes, which contained water. Sometimes they would creep out of
the water, and again would go into it. They seemed as if they were in
search of something which they had lost. It was now evident that their
object was to find some convenient place in which to undergo their
transformation into pupæ, but they did not like the boxes in which they
were confined, and several even died. I began to despair of seeing
their metamorphosis; which gave me much regret, as I had a great desire
to become acquainted with their whole history. In order to satisfy
myself, I went on the 26th of June to the spot from whence I had taken
them, in order to discover, perchance, some larvæ about to become pupæ,
and to ascertain the places they selected in which to undergo their
change. I had the gratification of being completely successful, and
of discovering not only the larvæ, but even several of them which had
shut themselves up in silken cocoons, and had not yet undergone their
transformation.

"The month of June appears, therefore, to be the period when these
larvæ prepare for their change of form. They do not leave the water
to accomplish it, the change taking place under water. They attach
themselves to the leaves of some of the younger aquatic plants, which
are at a suitable depth from the surface of the water. By means of
several silken cords the insect fastens together two, and sometimes
even three leaves, between which it spins an oval cocoon, composed
of very white silk. This cocoon is of a double structure; the true
inner cocoon, which is very white, is placed within an outer envelope
of silk, of a greyish or brownish colour. The envelope extends
considerably beyond the sides of the true cocoon (which lies loosely
in it); and towards one end there is a wide opening in it, the inner
cocoon being perfectly closed in on every side." The cut on the next
page represents the perfect insect and the pupa thus carefully provided
for.

[Illustration: _The Cut represents two leaves, between which the Worm
lies, the Cocoon itself, and the Larva._]

In this inner cocoon there is not so much as a single drop of water!
The pupa could not exist in it if it were not full of air; and the
difficulty is how to fill a little cell with air which is already
buried many inches under, and on every side surrounded by, water. De
Geer states that he did not find a particle of water in all the cocoons
which he opened. In order to ascertain whether or not it was really
necessary for the pupa to be thus carefully housed in a silken ball
full of air beneath the water, he took out several pupæ and put them
into some water in a saucer. At first they swam, but presently they
sank to the bottom. They lived for several days, but ultimately every
one died, showing plainly that the air-cell was absolutely necessary to
their existence.

[Illustration: _Pupa and perfect Insect._]

Yet, although these pupæ were air-breathing creatures, strange to
say, De Geer found that if taken from their little cells out of the
water, they shrivelled up and died. He put several in a dry box, and
invariably found that in a short time they were dead. He imagined,
with great probability, that the cause of their death was the
evaporation of their fluids, which of course does not take place when
they are enshrouded in their cocoons, and surrounded on all sides with
water. He made one more experiment with them, which was as follows:--He
took several out of their cocoons, and placed them in water in such a
manner, that one of their sides was in the air, while the other was in
the water; he kept them for a considerable time in this position, and
he had the pleasure at its expiration of seeing them become perfect
insects, just as if they had never left their cocoons. The necessity of
both air and water to their well-being was thus clearly proved.

How can we sufficiently admire the ingenuity and skill displayed by
this insect in the execution of its difficult task! When a human
engineer wishes to build under the water, he must have recourse to
the most cumbrous and powerful mechanism to enable him to effect his
object. Piles must be driven into the bed of the river so closely
as scarcely to allow any water to come through; a steam-engine must
be fixed close by, to pump out all the water from the space thus
enclosed; and a number of men must labour hard to stop up the chinks,
where the water comes pouring in. Thus men, and machines of great
power, and in sufficient number, are requisite to enable the most
expert engineer to form a cavity at the bottom of the river's bed.
What if we were to give him as a problem, to build a cell which should
be perfectly water-tight and filled with air, without allowing him
to employ any of these means, and to insist that it should all be
done without his coming up to the surface of the water at all for
anything? He would probably tell us it was impossible. Not so the
insect; it, though on all sides surrounded with water, actually spins
a web in the waves, and fastens it by cables of sufficient strength to
adjoining plants, and afterwards forms a water-tight cell in which it
shuts itself safely up secure against the invasion of enemies, or the
intrusion of a drop from the element in which its cell floats and is
moored.

[Illustration: _Pupa of the Ephemera, showing its gill-like Organs._]

All pupæ of aquatic habits do not, however, possess this remarkable
faculty of surrounding themselves with air even in the midst of the
water; and these would certainly perish unless means existed for them
also to inhale the vital air. These means are found in the endowment
of them with the power of swimming. Surely our readers must often have
seen the wriggling movements of certain little blackish objects, which
are to be found in every stagnant puddle in the summer. Many of these
are the pupæ of various species of gnats; and when we watch them come
darting upwards by a succession of flaps with their tail, until they
reach the surface, where they remain for a short time, we see the
means by which, although they live immersed in water, they are enabled
to breathe the air. For if we scrutinized them a little narrowly, we
might detect on each side of their largest extremity or head, a pair
of minute tubes which open into the air at the surface of the water.
It may sink beneath the water for a time without inconvenience, and it
is soon found plunging upwards, anxiously seeking to thrust its tubes
into the air. In the _larva_ state the gnat breathes by its tail, in
the pupa state by its _head_! The pupæ of some aquatic insects breathe
like the larvæ of the same insects by organs like gills. That of the
ephemera shown on the last page is an instance.

The curious apparatus of a telescope-like air-tube of the rat-tailed
insects, described in a former page, will not be forgotten by the
reader. It may interest him to learn that there is another little
creature which, in the pupa state, is furnished with a somewhat similar
apparatus. These pupæ have not the same power of swimming with the
last, and therefore require a special provision to meet the necessities
of their case. They are plunged some way down in the water, and air is
conveyed to them by a hollow tail-like tube, which is always found to
open on the surface of the water. It is a curious thing to contemplate
these little creatures, so beautifully provided for in this manner.
Secure of all they need in the supplies of air furnished to them by
their tube, they rest peacefully in the waters, unmoved by any of the
accidents which occur to surrounding creatures, and patiently awaiting
the hour which is to behold them rise from their watery bier, never
more to return. Let us so likewise rest in assurance of our Heavenly
Father's love and care for us, knowing that every want will be supplied
to his children by Him, who has said, "I will never leave thee nor
forsake thee."




CHAPTER IV.

VARIETIES AND AGE OF THE PUPA.


Although we are anxious not to attach too much importance to mere names
in this little work, and rather to keep the reader's attention fixed
upon the really essential truths of the "Life of an Insect," it is
expedient that we should mention that while all pupæ may be divided
into the two classes, _active_ and _inactive_, yet there are several
very striking variations in them, which are more remarkable than
those of larvæ. These it is proper here to mention, in order that the
reader may be spared the perplexity which would otherwise ensue, were
he to imagine that all inactive, or all active pupæ, were pretty much
alike. Let it never, however, be forgotten, that it is no matter what
the variation in form may be, nor does it matter whether the insect
is active or inactive, while in this state of passage from the larva
to the perfect form, it is always neither more nor less than a pupa.
Through this stage all perfect insects pass, although they may put
on various forms and aspects while they are in it, and may possess
various, and, perhaps, very opposite faculties during its continuance.
If this important fact is borne in mind, there will be no risk of being
misled by the confusion of sounds and names, which some have been
pleased to encumber insect history with.

In order to form a clear conception of these variations, reference may
be made to the engraving on the next page, in which we have caused to
be represented the five different kinds of pupæ, as they were named
and classified by Linnæus. This plate will sufficiently manifest the
necessity of an explanation upon the subject of the variations of pupæ;
for few persons in examining it would form the remotest idea, that
all the insects there represented are really and truly in the pupa
state. Some look so like the perfect insect, that it would be almost
impossible for any one only slightly acquainted with insect history to
believe them to be in what is in reality a transition stage from the
larva to the perfect form.

[Illustration: _Various forms of Pupæ._]

I. The insect, No. 1, is a pupa called the _Complete_, because it is
_active_, and has many of the parts of the perfect insect. The pupa of
the spider is an instance.

II. The insect, No. 2, is a pupa called the _Half-complete_, or
semi-complete. It is also active, resembles the perfect insect, but has
only the rudiments of wings. The grasshopper is an instance of this
kind of pupa.

III. The insect, No. 3, is a pupa called the _Incomplete_. It is
_inactive_, but possesses rudiments of legs and wings. The common wasp
is represented as an example of this kind.

IV. The insect, No. 4, is a pupa called the _Obtected_.[K] This pupa
has its upper portion encased in the peculiar manner represented, the
chest and lower portion being distinct. The butterfly pupa belongs to
this division.

V. The insect, No. 5, is a pupa called the _Coarctate_.[L] In this case
the pupa is enclosed within its larva skin, which forms a globular
or oval case, the pupa lying loosely in it as if it had shrunk to a
smaller size. The pupa of the blow-fly is an example.

Such are the five variations of pupæ, as they were recognised by
Linnæus--the _Complete_, _Half-complete_, _Incomplete_, _Obtected_, and
_Coarctate_. They are sufficiently minute for ordinary purposes: and it
will possibly save the reader some confusion of ideas to endeavour to
fix them in the memory; so that when looking at an insect whose pupa
state may not be so very characteristic as that of the blow-fly, or
butterfly, he may still be able to say with confidence, that although
it is unlike these, it is nevertheless a pupa. On all subjects nothing
is of so much importance as clearness of ideas. It is better to know
only a few things, and to understand them clearly, than to have a
confused and indistinct knowledge of a great number. It has been,
therefore, simply and entirely with a view to obviate this state of
things in the mind, that these definitions of the different kinds of
pupæ, which may have appeared not altogether interesting, have been
given.

Having fulfilled this duty, we may now proceed to the more agreeable
task of ascertaining some interesting facts relative to the insect's
life and age in the pupa state. We have already seen that the insect in
the larva state often arrives at a very respectable old age; indeed,
in this state insects live longer than either in the pupa or perfect
states. But pupæ also attain to a very fair number of days, sometimes
living as long as two years in that state. Often, however, they are
not more than a few days in this condition, and the insect, after a
short repose, springs forth a new and active being. But it has been
found that insects live a longer or shorter period in the pupa state
according as the temperature of the air is cold or hot. Thus, for
example, when the larva of a moth has become a pupa in the early part
of summer, the pupa state will generally not last beyond a fortnight.
But if, on the other hand, the larva becomes a pupa late in the autumn,
the pupa state will last until June in the next year: thus manifestly
teaching us that according as the weather is mild and genial the pupa
state will be shortened; or according as it is cold and rigorous it
will be increased in duration. The ingenious Réaumur determined to put
these singular facts to an experimental test; and as his results are
in the highest degree interesting and important, we shall proceed to
submit an abstract of them to the reader's notice.

In casting about for the means of exposing the pupæ he was about to
experiment on, to a warm and equable temperature, Réaumur determined
to conduct his first experiments in the Royal Conservatories, which
were always carefully heated, and in which, as he with French _naïveté_
expresses it, "summer reigned in the depths of winter." In the month
of January he carried thither a number of boxes containing pupæ of
different species. The result was precisely what he had expected:--in
the midst of a severe winter a number of butterflies appeared in his
boxes, many of which would not naturally have made their appearance
until the months of May, August, or even September; thus shortening the
pupa state from four, seven, or eight months, to a fortnight, or to
five, or to six weeks in different instances. Five or six days seemed
to be equal to a month of the natural temperature. The butterflies thus
developed were in no respect different from those which are brought
into activity at the natural period. They were as active and perfect,
as if their time and place of birth had been the green fields, instead
of amidst the strange vegetation of these splendid Conservatories.
Several of the mother insects deposited their eggs, accomplishing the
last act of their existence as if summer had come, and died while
the frosts and snow held all external nature yet in bondage. Not
only, therefore, was the duration of the pupa state in these insects
shortened, but their whole life was thus abridged by several months.

In November of the same year Réaumur recommenced his experiments,
and again exposed a number of pupæ to the genial influence of these
hot-houses. The result was the same. In the first week in December
butterflies appeared, which would not, in natural circumstances, have
been developed earlier than the May of the next year. There were some
pupæ, in particular, whose development he watched with great interest.
These pupæ belonged to a beautiful species of moth, which has two
broods in a year; that is, it lays eggs in May which become butterflies
in July, and then again lays eggs which become pupæ in August or
September, but do not become butterflies until the following June. He
was curious to see whether this second brood, instead of waiting for
several months, would, like the first, disclose its butterflies in a
considerably shorter time, now that it was exposed to the warmth of
the Conservatory. Such actually proved to be the case; and thus two
generations of these butterflies were obtained in one year. Alluding to
the depredations of caterpillars, he quaintly remarks, "This certainly
is not a secret which appears very profitable at present; but who can
tell whether that which is useless to us to-day, may not possibly
become of value to-morrow? Could we discover some new species of larvæ
which would supply us with as good a silk as that of the silk-worm,
and might be more easy to rear, but which only produced one generation
in each year, and if it lived upon leaves which could be found all the
year through, we might avail ourselves of this means of increasing the
number of its broods." This remark deserves much consideration.

He was now anxious to try whether, by applying a more equable method
of warming, he could succeed in hatching pupæ as he had done in the
hothouse. The idea occurred to him of endeavouring to hatch them _under
a hen_. He concluded that the warmth of the mother's breast would quite
as easily hatch the insects, as it does the eggs. But there was this
obstacle in the way: How could he prevent the fragile and tender bodies
of the insect pupæ from being crushed and killed by the weight of the
hen's body? and, as we would also suggest, How could he ensure that the
bird would not actually have eaten up the objects of his care? Aware
of the fact, that, when a hen is in the humour to sit, she will often
allow smooth stones to be placed among her own eggs, he anticipated
no difficulty on that score, and he hit upon the following ingenious
experiment:--He procured some hollow glass balls which he had caused
to be made as nearly as possible similar in size and shape to the eggs
themselves. Into these, by an opening at one end, he introduced seven
or eight pupæ, and stopped the mouth up with a cork, but so as to
allow a free communication with the external air by paring off a piece
from the side of the cork.

Thus prepared, he put the glass egg together with the others in the
nest. The hen was a little more sensible than Réaumur had given her
credit for; and though she did not thrust the egg out of her nest,
she removed it to the outside, where she was so obliging as to permit
it to remain; and as it was here just as warm as if it had been in
the centre of the eggs, Réaumur did not attempt to interfere with her
arrangements. A great deal of moisture arose from the bodies of the
pupæ, and condensed like dew on the sides of the glass; but after a
day or two this disappeared. The reader may now be anxious to learn
the result of this experiment. It was equally successful; indeed, it
was more so than the preceding, for in the afternoon of the _tenth_
day a pretty little butterfly was seen within his glass egg, being the
first that had appeared of the eight pupæ, and the first ever hatched
under the bosom of a hen! The remaining pupæ, all but two, appeared
soon after; these two died. Perhaps the warmth of their glassy cell
was too violent for them, for it was found by the thermometer to be
two or three degrees above blood heat. The whole six pupæ were born
in less than six days, while others of the same species in a box in a
window-seat were not developed until twelve days later. As the heat
thus obtained seemed too violent for pupæ to be artificially reared
with success, Réaumur suggests that many variations might be made
in the experiments, which would have the effect of moderating its
amount. These experiments decided in the most satisfactory manner the
quickening influence of increased warmth upon the pupæ of insects.
Réaumur now became anxious to try the effects of the opposite state of
temperature, and to ascertain whether exposure to cold would exercise
any effect upon the pupæ. It was reasonable to imagine that as warmth
had hastened forward their development, cold would retard it.

Réaumur determined to try what would be the result of putting his pupæ
in their boxes in a cellar, and taking proper care to preserve them
from the damps of such a situation. He put them there about the end
of January. In ordinary circumstances these pupæ would have become
butterflies in the month of July in the same year. July came, and
we can conceive the curiosity with which the ingenious experimenter
went down, as he tells us, to his cellars, to see if any change had
taken place in the pupæ. July passed away; August also passed by,
yet the pupæ still slumbered on in their original form. Réaumur left
Paris in September, and did not return until the November following.
He immediately went in quest of his pupa-charge, and found them still
unaltered. Were they dead? Placing one in his hand, it soon began to
exhibit such symptoms of motion as plainly showed that it was alive.
Winter closed over them still in the pupa form. The spring of the next
year dawned upon them, but they were insensible to its influences. "And
even now," cries Réaumur, in the month of August, just two years from
the time they left the larva form and became pupæ, "they are in perfect
health, in excellent condition, and would all become butterflies very
soon if I were only to expose them to a warm summer's influence."

"These extraordinary facts," observe Messrs. Kirby and Spence, "lead
us to a very singular and unexpected conclusion,--that we have the
power of lengthening or shortening the life of many insects at
pleasure--that we can cause one individual to live more than twice as
long as another of the same species, and _vice versâ_. Had Paracelsus
made this discovery, it would have led him to pursue his researches
after the elixir of immortality with redoubled confidence, and would
have supplied him with an argument for the possibility of prolonging
the life of man beyond its usual term, which his sceptical opponents
would have found some difficulty in rebutting. Even the logical Réaumur
seems inclined to infer from it, that this object of the alchemist's
was not so chimerical as we are wont to conclude. He confesses,
however, that, if it were to be attained only by the same process as
effects the extension of an insect's life,--by prolonging its state
of torpor and insensibility,--few would choose to enjoy it on such
conditions. The man of pleasure might, perhaps, not object to a sleep
of a hundred years, in the hope of finding something new under the
sun when he awakened; and an ardent astronomer would probably commit
himself with scientific joy to a repose as long and as sound as that
of the Seven Sleepers, for the chance of viewing his predicted return
of a comet on stepping out of his cave. But ordinary mortals would
consign themselves to the perils of so long a night with reluctance,
apprehending a fate no better than that which befel the magician who
ordered himself to be cut in small pieces and put in pickle, with the
expectation of becoming young again."

But this is in every respect erroneous as a deduction from these
experiments on insects. It must not be forgotten, that these
experiments were made at a time of the insect's life when it is
naturally torpid, and not upon the perfect insect. Had Réaumur
attempted to prolong the life of a butterfly, he would have failed
completely, that is, if he had adopted the same means; so that all
which we can infer from these results is simply this, that we can only
prolong or shorten the pupa state, which is a state of torpidity, a
kind of half-way between life and death.[M] The human frame knows no
such state after birth as can be properly compared to the inactive
pupa state of insects; and consequently all reasoning founded on what
may take place in such a state under the particular circumstances
described, is without foundation. Besides all this, God has himself
fixed a limit to human life; and we are expressly assured by his word
of truth, that "it is appointed unto man once to die;" and though by
reason of strength we may reach far into a long life, yet the hour
comes at last, and the green earth closes over the only mortal portion
of a man. Undoubtedly had Réaumur prolonged his experiments, he would
have found that death, or the transformation of the pupa, would
ultimately have taken place.

As yet, we are not aware that any practical results on a large scale
have followed from Réaumur's interesting experiments. It has been
already remarked, that in countries where the silk-worm is reared, it
is the custom to hasten the hatching of the eggs by women carrying
little packets of them about their person. But this is only to
bring forward the development of the larva state. Perhaps the time
anticipated by Réaumur may arrive, when insects may be hatched under
hens! or in hatching machines, so as to obtain two instead of one
brood of eggs and larvæ in a season. Réaumur suggests that the great
and wealthy who have good hot-houses, might give all the appearance
of summer to them by introducing pupæ in winter, which would soon be
hatched, and butterflies or other insects might be seen flying about
in December or January, from flower to flower! But he forgot that
gardeners generally are rather averse to the presence of insects at
all, and particularly to the all-devouring larvæ of many species of
butterflies, which would soon commit sad havoc among their choicest
plants. We may recommend such experiments to the reader as highly
interesting and easy of performance in a common sitting-room, where a
fire is kept in winter, with no other apparatus than a tin-box, or a
glass jar of very moderate size; even a pill-box would answer every
purpose.

Some curious experiments on pupæ of another kind were also performed
by Réaumur. He varnished them over with various varnishes, and found
that the pupæ thus varnished were developed several weeks later than
others of the same species unvarnished. He tried similar experiments
upon eggs, and found that the eggs of a hen would keep fresh for a very
long period if they were entirely coated with some kind of varnish.
This proved a most useful experiment, for it is now common all over the
Continent to preserve eggs by covering them either with oil or butter.

We may learn, in reflecting upon the facts brought to light by this
ingenious entomologist, with what admirable care and skill the Great
Creator has arranged the period to be occupied by the insect in the
pupa state. It has been wisely ordained by these arrangements that the
insect shall not be developed until the season when its proper food is
to be found, or when a proper position for placing its eggs is to be
discovered. The gay flutterer, so tender in its frame, must not be born
amid the snows of winter, or in the ungenial days of early spring; its
pupa, therefore, requires the warm influences of July and August before
it will undergo its change. If it were born earlier than that time it
would unquestionably perish, and the insect would become extinct; if
later, the same result would take place, for it would fall into the
killing power of the early winter evenings. As it is, all is well.
The insect and the day are made for one another; for it the flower
blossoms, and the warm air breathes, and all nature is spread out in
warmth and happiness. Its career run through, it departs from the scene
it has enlivened, leaving behind, just at the proper time, and in the
proper place, the eggs which are to become quickened, live, and die,
like itself, all in their appointed time. We thus perceive that it is
chiefly the increasing temperature of the air which fixes the time of
the insect's duration as a pupa, and sets in movement all the great
chain of the events of external nature. In what way an increase of
warmth thus acts we are still unable to say; perhaps, indeed, we may
never be able to tell. Neither can we understand how it should be, that
the principle of life should be ready at a moment's notice to complete
its work in the perfection of the insect, and yet held in abeyance
by a few degrees of a lower, or quickened into activity by a few
degrees higher, temperature. We know that this has been God's doing,
and marvellous it is in our eyes; but the wisest of men feels himself
ignorant if asked the question, how it is thus arranged? Truly none
but a God infinite in wisdom as well as love would take such thought
for so humble a creature as a poor insect; but let us not forget that

            ----"each crawling insect holds a rank
    Important in the plan of Him who framed
    This scale of beings,--holds a rank, which, lost,
    Would break the chain, and leave behind a gap
    Which Nature's self would rue."

The duration of the insect in the pupa state, though variable, is,
without doubt, limited, and sometimes it is fixed to _an hour_, quite
irrespective of all external circumstances. The most remarkable
example of this kind occurs in the case of the insects whose larva we
have already mentioned--the _Ephemera_. These insects appear with the
greatest regularity, issuing from the waters of the Seine or Marne, in
France, between the 10th and 15th of August. The fishermen call them
_manna_; and when their season is come, they say, "the _manna_ begins
to appear," or "the manna fell abundantly last night," alluding, by
this expression, either to the astonishing quantity of food which the
insects afford to the fish, or to the large quantity of fish which they
then take. The fishermen expect them with the greatest confidence
during these few days, nor are they ever disappointed. Millions upon
millions suddenly rise into the air between eight and ten o'clock
in the evening, and this generally for three successive nights.[N]
Whatever be the temperature of the atmosphere, whether it be cold or
hot, these flies invariably appear at the same hour in the evening,
that is, between a quarter and half-past eight; towards nine they begin
to fill the air; in the following half hour they are in the greatest
numbers; and at ten there are scarcely any to be seen. So that in
less than two hours--and these always the same--this infinite host of
insects leave their pupa state, become perfect insects, perform their
appointed work, and vanish. The same phenomenon of regularity of limit
to the pupa state occurs also in other insects, though, perhaps, less
strikingly. Some insects constantly leave the pupa at break of day;
others in the full tide of noon-day, and others when the shadows of
declining day come over the landscape. These, however, are certainly
exceptions to the general rule, which appears to lay down no precise
period of the day or month when this state is ended, and the perfect
state is entered upon; but a limit, nevertheless, exists, mainly
dependent for its appointment upon the external influences of warmth
and air.

This limit attained, we are brought to the next point in the history
of the insect pupa. The beautiful organization of the perfect insect
has been going on under the dry and repulsive exterior. Its delicate
limbs, exquisitely wrought wings, and the other most wonderful organs
with which the perfect insect is furnished, are now completed. Nothing
remains but to cast off the slough of its pupa case; and it will then
be set free to range whither it will in the great atmosphere into which
it will emerge. If the reader has been watching these insect changes
with the natural object before him, he will immediately confirm our
statement, when we mention that it is often possible to tell when
the pupa case is about to disclose its occupant. The general form of
the limbs is often very clearly to be seen, and the movements of the
included insect become much more sensible and conspicuous. If the
beautiful gilded pupæ, called, as we have before said, _Chrysalides_,
or _Aureliæ_, have been thus nursed with a view to observe their
change, it will be noticed that they lose entirely that golden
lustre which made them at first such attractive objects. These signs
infallibly foretoken the approaching transformation.




CHAPTER V.

THE GREAT CHANGE.


We must now spend a short time in narrating the particular
circumstances which attend this interesting event,--the extrication
of the insect from its pupa case. We shall, in the first place, speak
of such pupæ as are not aquatic, and, afterwards, of the singular
ones which are so. In the case of the butterfly, which, as we have
recommended repeatedly its being nursed and bred, it will be expedient
to mention first, the extrication of the insect is, comparatively
with some others, a very simple operation. The insect within is seen
to struggle for a time, twisting its body in various ways, until at
length a longitudinal slit appears down the middle of its thorax. The
slit extends gradually along the head, and down the parts which compose
the breast, until the insect emerges from the outer case. The inner
membranes are now to be removed, and this, after a little time, is
fairly accomplished, and the butterfly emerges, and, leaving the pupa
skin behind it, by-and-by plunges for the first time upon the soft
waves of the summer air. This is one of the simplest of these methods
of extrication.

[Illustration: _Pupa of Goat-Moth._]

A very natural difficulty will arise in the mind as to what possible
means of escape can be granted to such insects as live in the pupa
state in the interior of old trunks of trees, or even in little caves
of the earth. These cases have all been satisfactorily provided for,
puzzling as they may seem. Take, for instance, the pupa of the great
goat-moth, the _Cossus ligniperda_, of which we give a representation
here. This creature lies buried in a deep excavation, formerly made by
itself when in the larva form, inside the trunk of a willow. How is
it to get back to the hole at which it entered? Without legs, without
any other apparatus by which it might drag itself forward, one would
say it is in a hopeless case; it must lie there and perish, for there
appears no way of extricating it from its den. But not so. Helpless as
it appears, it will certainly make its way out, and taste the sweets
of liberty, and be wafted along the fields of air. But how? Let us
suppose a man in such a condition; let his feet be bandaged together,
so that they cannot move; let a strait-jacket be put upon his body, and
secure his arms and hands; after this, let a leathern bag be put over
his head, and tied down round his middle; then put him in a cellar,
and bid him work his way out and up the stairs until he reached the
front door, where he must undo his bandages, and slip himself out of
his strait-jacket and hood; after which, he may go wherever he likes.
What a feeling of despair would fill the poor prisoner's mind, promised
his release on condition that he should accomplish it in that way! To
him it would be a task altogether impossible, even though his life were
offered as the reward of his success. It is not less a question of life
and death to the insect than it might be to him; yet its extrication is
accomplished, not only in a very simple, but in a very easy manner.

If the reader will carefully examine the representation of the insect
given in the last page he will notice that the pupa case is provided
with certain sharp points, which are all directed towards the
tail of the insect; these sharp points are called by entomologists
_adminicula_. They are of infinite consequence to the insect. Who has
not himself performed, or been the subject of, the trick of causing
a grain of barley to creep up the sleeve? The manner in which it is
gradually pushed up is strikingly similar to that in which the pupa of
the _cossus_ is forced upwards and out of its wooden gallery. It will
be readily supposed that, in consequence of the peculiar direction
assumed by the tooth-like processes in question, it will be very
difficult to push the pupa backwards, as the points would catch in any
obstacle and arrest its progress in that direction; but they offer no
resistance to its moving in a forward direction. The manner in which
the insect proceeds, then, is as follows:--Being capable of slightly
shortening and lengthening the lower part of its body, which is the
part thus provided with hooks, it begins to push backwards, but the
hooks catch in the sides of the wood, and thus prevent it from moving
back, and it is, consequently, actually driven forwards; and so it
continues to thrust itself gradually forwards in this simple manner,
just as a boy with his hands tied might thrust himself forwards as he
lay on the ground, by pushing against any object with his feet. In this
way the patient creature moves, we may be sure, by very slow degrees;
but that matters little; it moves until it has at length reached the
opening of its gallery outside the tree, where it may often be seen
sticking out half way. Here, by a remarkable instinct, it ceases to
move forwards, for it would otherwise tumble down, and probably destroy
itself. At length, after violent struggles, its swathing bands are all
either torn asunder, or slidden off, and the insect wings its way in
unrestrained freedom far from the scene of its triumphs of patience
and hope. The pupa of the "father long-legs" makes its way up from the
subterranean chamber in which it has so long been sheltered, fed, and
protected, and reaches at length the surface of the ground, where it
becomes the perfect insect.

[Illustration: _Swelling of the Head of the Fly._]

But other pupæ, although not, perhaps, quite so arduously placed as in
the last instance, nevertheless present us with an extremely difficult
puzzle, as to how the included insect is to be extricated from its
swathing bands. The common flesh-fly, or blow-fly, for instance, in
the pupa state is shut up in a membranous case, out of which there
seems no escape; but there is a way, and the manner in which the insect
gets out of its prison is a remarkably curious one, well repaying the
trouble of a little close observation. At the larger end, under which
the head of the fly lies, and from which it always issues, there is
commonly a sort of lid which can be pushed off like the lid of a box,
and the insect can then walk out at pleasure. But in the case of the
pupa of the blow-fly this lid is not very easily removed, and the fly,
therefore, is furnished with a most ingenious method of thrusting it
off. On opening the larger end of such a pupa, if the fly within is
ready to come out, a most curious phenomenon will be seen. The insect
moves towards the lid, and there begins to blow out its head in the
most extraordinary manner, swelling it to twice its natural size; a
moment after it will resume its natural size; then again it will puff
it out, making its two eyes to start asunder, and its head to assume
several different shapes in succession! Two representations are annexed
of the striking figure of the insect's head when it thus causes it to
swell out. After repeating this action several times, the fly emerges
from the pupa. The cause of this remarkable dilatation is the filling
of a membrane, situated at the middle part of the head, with air, by
which it is blown out into a sort of bladder as large as the head
itself. This acts as a kind of lever, and eventually pushes up the lid
of the pupa case, allowing the insect to make its exit unmolested. This
part generally disappears afterwards, and the head becomes alike firm
and unyielding in all its parts; but it may, in at least its rudiments,
be seen even in the head of the adult fly, by slightly pressing its
head between the fingers, when it appears as at _x_ in the cut.

[Illustration: _Head of a Fly magnified. It shows opposite the letter x
the remains of the membranous bag._]

More singular still are the circumstances which mark the exit of the
insect from the pupa case in other instances; and yet more strikingly
than those narrated, do they exhibit to us the amazing exercise of the
Divine attributes of wisdom and forethought in the case of these humble
beings. The larva of a species of moth, which dwells in a wooden cell
scooped out of the poplar tree, to which there is no door by which
it can escape readily, gnaws away the wood until it leaves only an
extremely delicate layer between it and the outside of the tree, which
is as thin as writing paper. This done, it enters into the pupa state.
Its time in that condition being accomplished, it moves itself by the
same contrivance as the _cossus_, and actually pushes through the thin
layer, and appears on the outside of the tree, thus making its escape
from prison by pushing down a part of its prison wall!

An instance described by the naturalist Bonnet is yet more ingenious
in the arrangements by which the insect escapes. While in the larva
form it takes up its abode inside the leaf of an ash, curiously rolled
up into a cone; and then, after a time, it becomes a pupa, forming a
silken cocoon of a very slight texture, and, therefore, easily ruptured
by the insect, which it suspends like a hammock in the midst of its
habitation. It is the closely joined sides of its leafy dwelling that
form a barrier which, were it not for the precaution of the larva,
would be impenetrable to so small and weak an animal. But, like the
last-mentioned, this larva seems to be aware of the feebleness of its
next condition, and gnaws in the leaf a round opening, taking care
not to cut through the exterior thin layer of tissue, or _epidermis_.
This door is to serve the insect for its exit in due time. But in
proportion to its bulk, its green chamber is of considerable size.
How, then, shall the insect know the exact place where its portal is
situated? How, without a clue, shall it discover in its dark abode the
precise circle which requires only a push to throw open its gate? Even
this is foreseen and provided for. Out of all other positions in which
the little hammock, of which we spoke, might have been hung, and they
are numerous, the larva has been directed so to place it, that the
silken cord which suspends the head is fastened close to the side of
the door which it has previously constructed; and the insect, when it
emerges from the pupa, guided by this thread, like Theseus, makes its
way out of an apartment which, but for this contrivance, might have
been to it a labyrinth as inextricable as that of Minos. Other insects
adopt the same precaution of gnawing a doorway for the escape of the
perfect insect, only leaving a sufficient thickness of outside tissue
to protect the helpless pupa within from the invasion of enemies from
without.

[Illustration: _Cocoon of Emperor Moth._]

Upon the pear or willow tree may sometimes be found an illustration
of escape from the pupa, altogether well deserving our notice. In
such situations the brown flask-shaped cocoon of the emperor moth may
occasionally be discovered. In structure it is composed of a solid
tissue of layers of silk, almost of the texture of parchment; but
at the narrow end, or that which may be compared to the neck of the
flask, it is composed of a series of loosely attached longitudinal
threads, converging like so many bristles to a blunt point, in the
middle of which is a circular opening, through which the moth makes
its escape, the threads readily yielding to pressure from within,
and acting somewhat on the principle of the wires of the opening to
a rat-trap, or the willow cricks of an eel-trap. The silk of its
cocoon is of so strong a texture, and so closely gummed, that had
both ends been similarly closed, the egress of the insect would have
been impracticable. But, it may be thought, such a cocoon is exposed
to the attacks of a number of insect enemies, who might easily find
entrance to it at the opening thus left at one of its ends. This
source of peril has been foreseen. Within the exterior funnel-shaped
end, at some little distance down, the insect has constructed a second
funnel composed of a similar circle of needle-pointed threads, which,
proceeding from the sides of the cocoon, converge to a point, and form
a cone through which not the smallest aperture is left. From the arched
structure of this singular dome, and from the fact just mentioned, that
no visible opening can be discerned in it from without, it is rendered
quite impenetrable to the most violent attacks of besiegers, while it
yields to the slightest pressure from within, and allows the insect to
emerge from its cocoon with the utmost facility. When it has passed
through it, the elastic threads resume their former position, and the
empty cocoon presents just the same appearance that it did before.
A celebrated naturalist (Rösel), was sorely perplexed at this, the
first time he had the gratification of watching the insect escape. He
states that he could scarcely help thinking that there was something
supernatural in the appearance of one of these fine emperor moths in
a box in which he had put a cocoon of this kind; but in which he could
not discover the slightest appearance of any insect having escaped from
it, until he slit it longitudinally, and then found it to be empty!

Mr. Rennie mentions an instance, perhaps not so ingenious, but equally
curious, with this history of the proceedings of the emperor moth, in
a little insect, also a moth, which also dwells upon the willow. It
spins an elastic shroud for its pupa, of the singular shape of a boat
with the keel uppermost. Its first step is to spin two walls of whitish
silk of the required form; and when these are completed, it draws them
forcibly together with elastic threads, so placed as to retain them
closely shut. The passage of the moth out of this cocoon might have
struck Rösel with still greater surprise than he had felt at witnessing
that of the emperor moth; for in that cocoon there was at least no
apparent difficulty to prevent the egress of the insect, as the opening
existed in it at one end, whereas in this there is no opening at all.
The insect escapes at the joining of the sides, the threads giving way
in a particular spot; and the sides, though originally requiring force
to draw them together into the requisite form, become so elastic as to
close again when the moth has passed between them, and made its escape.
The cocoon preserves precisely the same form after the insect has
quitted it as before, and it is impossible, by the naked eye, to detect
the place of its exit.

As a general rule, insects make their escape from the pupa case head
foremost; but there occurs a very singular exception in the case of
some of the gall insects. The males of these insects contrive to make
their escape out of the pupa case, formed of the dried skin, tail
foremost; and as they thus back out of their dwelling, their wings are
necessarily turned backwards over their heads; but a little exercise
soon puts the ruffled insect in proper plume again, and the wings
resume their customary position.

Some curiosity may be felt to know in what way the silk-worm moth
escapes from the double prison,--the pupa case, and the cocoon,--in
which she is concealed. How is the moth to make its way through the
dense mass of fibres all glued together, which walls her in on every
side? Her delicate wings and body would never endure anything like the
severity of the struggle necessary to enable her to force her way
through this, to her, solid and resisting mass. Though much attention
has been paid to the transformations of this particular insect, it
is somewhat curious that it is still a matter on which opinions are
divided, as to how the insect succeeds in making its egress. Some
suppose that the eyes, which are the only hard organs of the head, are
the instruments by which the threads are divided, their numerous minute
facets serving the purpose of a file. Others hold the belief that the
insect pours out a fluid which acts upon the gum and silken fibres of
one end of the cocoon, and so softens them that they easily give way
to the slightest pressure from within. "Perhaps the two opinions,"
observe Messrs. Kirby and Spence, "may be reconciled by supposing the
silk-worm first to moisten, and then to break, the threads of the
cocoon. In those that are of a slighter texture, a mere push against
the moistened end is probably sufficient; and hence we find in so many
newly-disclosed moths the hair in that part wet and closely pressed
down."

It has been supposed, in cases where the cocoon is a hard, almost
wooden cell, that the feeble insect prisoner within is provided
with a peculiar chemical fluid, of greater powers of solution than
are requisite in the last instance. The cocoon of the "pussmoth,"
in particular, is so hard and dense, as to resist even the point of
a penknife; and the insect it holds confined within it is a weak
creature, totally unprovided with any apparatus fit for penetrating
walls so hard and dense as these. What is it to do? "Here," observe the
writers last quoted, "the eyes are clearly incompetent; nor could any
ordinary fluid assist their operations, for the gum which unites the
woody particles of the cocoon is indissoluble in _aqueous_ menstrua.
What an aqueous solvent cannot effect, an _acid_ is competent to; and
with a bag of such acid our moth is furnished. The contents of this
she pours out as soon as she has forced her head through the skin of
the pupa, and upon the opposite end of the cocoon. The acid instantly
acts upon the gum, loosens the cohesion of the grains of wood, and a
very gentle effort suffices to break down what was, a minute ago, a
strong barrier. How admirable and effectual a provision! But there is
yet another marvel connected with it. Ask a chemist of what materials
a vessel ought to be to contain so potent an acid; he will reply,--Of
_glass_.[O] Yet our moth has no glass recipient; her bottle is a
membranous bag; but of so wonderful a fabric as not to be acted upon by
a menstruum, which a gum, apparently of a resinous nature, is unable to
resist! This fact can only be explained by the analogous insensibility
of the stomach to the gastric juice, which can dissolve bone; and it
is equally worthy of admiration. In both cases, the _vitality_ of the
membranous or fleshy receptacle secures it from the action of the
included fluid; but _how_, who shall explain?"

[Illustration: _Glazed Ant-hill of M. Huber._]

The naturalist, Huber, the patient historian of the ants, gives us a
very interesting account of the proceedings of these wonderful insects,
in actually _assisting_ the young out of their silken cases. These
pupæ are enclosed in a tissue of silk, of so compact a texture, and
formed of so strong a silk, as to render it impossible for the prisoner
within to rupture the fibres, and get out of prison. The worker ants,
therefore, are instructed by a heavenly Ruler and Guide to give
help to the prisoners, and to secure their egress. But how do these
indefatigable attendants ascertain precisely the moment when their aid
is required? The insect within has no power of voice to cry out for
help, nor those without, in all probability, the faculty of hearing, if
it could do so. It seems probable that they are acquainted with it from
some slight movements which take place within, which they ascertain by
means of their antennæ. Whatever it be, the attendants never interfere
at a wrong time. Their manner of proceeding is beautifully described in
the following words of this author:--"Several males and females lay in
their envelopes in one of the largest cavities of my glazed ant-hill.
The labourer-ants assembled together, and appeared to be in continual
motion around them. I noticed three or four mounted upon one of these
cocoons, endeavouring to open it with their teeth, at that extremity
answering to the head of the pupa. They began to thin it by tearing
away some threads of silk where they wished to pierce it, and at length
by dint of pinching and biting this tissue, so extremely difficult to
break, they formed in it a vast number of apertures. They afterwards
attempted to enlarge these openings, by tearing or drawing away the
silk; but these efforts proving ineffectual, they passed one of their
mandibles into the cocoon, through the apertures they had formed, and
by cutting each a thread, one after the other, with great patience, at
length effected a passage, of a line[P] in diameter, in the superior
part of the web. They now uncovered the head and feet of the prisoner,
to which they were desirous of giving liberty; but, before they could
effect its release, it was absolutely necessary to enlarge the
opening. For this purpose these guardians cut out a portion in the
longitudinal direction of the cocoon, with their teeth alone, employing
these instruments as we are in the habit of employing a pair of
scissors. To expedite the work some raised up a little slip cut out in
the length of the cocoon, whilst others drew the insect gently from its
imprisonment. When the ant was extricated from its enveloping membrane,
it was not, like other insects, capable of enjoying its freedom, and
taking flight; it could neither fly, nor walk, nor without difficulty
stand, for the body was still confined by another membrane, from which
it could not by its own exertions disengage itself.

"In this fresh embarrassment the labourer-ants did not forsake it: they
removed the satin-like pellicle which embraced every part of the body,
drew the antennæ gently from their investment; then disengaged the feet
and the wings, and lastly, the body, with the abdomen and its peduncle.
The insect was now in a condition to walk, and receive nourishment,
for which it appeared there was urgent need; the first attention,
therefore, paid it by the guardians was that of giving it the food I
had placed within their reach."

It is droll to add, and it may be some of our readers may feel somewhat
abashed at the fact, that these labourer-ants are extremely particular
in the observance of great order and regularity in their chambers;
and they therefore carefully sweep up all the cast-off coverings,
which are collected together, and deposited in one of the most distant
lodges of their habitation. Could man, with all the powers of reason,
and the faculties of an immortal being, have evinced a more striking
instance of careful, gentle, and patient assistance in the hour of need
than we see manifested in the case of these insects? Alas! how often
does man need to come to them to learn not only a lesson of wisdom
and order, but of the tenderest sympathy and affection. How often
lies a poor fellow-creature in the bondage of hopeless poverty, or in
the embarrassment of inextricable difficulties! How seldom does his
emergency meet with that resolute and thorough-minded earnestness of
brotherly love, which will patiently give him help and pity, until his
troubles are surmounted, and his steps set free!

It is time that we spoke somewhat upon the extrication of insects
from their pupa cases, even when under water. Here arises a great
difficulty;--the wings of the insects thus placed, if wet with water,
would be unfitted for flight, and would probably frequently lead to the
death of the insect by drowning. Yet it is to leave its sub-aqueous
abode, mount up through the waves overhead, and finally emerge without
a drop of water clinging to its body, and from the glassy surface of
the water it is to take its flight into the air. Some will be tempted
to exclaim,--"This is a clear impossibility!" Far from it. The little
worm so well known to anglers as the "caddis-worm," performs this feat
with the greatest ease, and in the following manner:--

[Illustration: _The Pupa-case, Larva and Fly of Caddis-worm._]

[Illustration: _Grating of the Pupa-case._]

It has been mentioned that the larva known under this name constructs
for itself a case of various materials in which it dwells at the bottom
of the waters, where the hand of the young angler knows well to find
them. This case is heavier than water, and consequently cannot float,
and so carry the insect to the surface. As the insect enters the pupa
state it weaves, at the entrance of its singular habitation, a grating
of silk, which, strange to say, is not only not softened and melted
away by the water, but hardens under it until it is as hard as gum.
This little grating is of a circular form, and fits exactly into the
opening, and is perforated with holes, so as to look something like
the gratings which cover our coal-cellar mouths in the pavement of
cities. These holes are for the purpose of letting in fresh water for
the respiration of the insect. Out of this under-water cell the insect
must make its escape. To enable it so to do the pupa is furnished
with two strong curved jaws, which are of no other use than to assist
it in making an opening in one of the silken doors of its case, as
they are cast off immediately afterwards, and there remains not a
vestige of them in the perfect insect. This opening made, the pupa
forces its way out at that end. But what then? How is it to reach the
surface, even now? Its legs, as will be seen by looking at the cut,
are furnished with a number of hair-like processes, which assist it in
swimming; it therefore, still enclosed in the waterproof coat--the pupa
skin--strikes upwards to the surface, and reaching it, its skin splits,
its impervious raiment is cast aside, and the insect springs from the
surface into the air without the minutest drop of water to impede her
flight, or injure the delicate tissue of her wings!

[Illustration: _Caddis-fly's Legs magnified to show the Hairs._]

[Illustration: _Escape of the Gnat from its Pupa-case._]

We may take another common insect for an illustration of this mode of
escape from the pupa, of an equally interesting kind. If the reader
will on some fine summer day resort to any place of standing water by
the road-side, he may probably succeed in discovering the emergence of
a number of _gnats_; and a very amusing occupation it is to stand by
and watch the insect,--this moment an occupant of the waters, and the
next darting in the air, a new and air-breathing form of existence!
About ten days after the gnat has become pupa, it prepares for leaving
that state and becoming a perfect insect by raising itself to the
surface of the water, stretching out its body there, the thorax, or,
in simpler language, the front enlarged part being raised above it.
Immediately the eye of the observer detects the fact that some change
is taking place in the insect; the enlarged portion cracks and splits,
and through this opening the head of the gnat makes its appearance;
then the trunk of the insect rises in a curious manner through the
breach, and more and more of its body rises, preserving all the time
a perpendicular position, so that it looks just as if it were rising
out of the water, and not out of the horizontal pupa case floating on
the surface. The upright body of the gnat now resembles a mast in a
boat, only that it is continually being raised higher and higher by
the gradual emergence of the insect. Its wings and legs are all folded
closely down its sides as is shown in the cut; and it has therefore no
power at all to prevent its being overset by a breeze, and drowned in
the little waves below; the lower portion of its body alone retains
it in this position, being as yet contained within the pupa case. No
ship-builder dare venture to put a mast of such proportions into any
of his vessels, for fear of their being top-heavy, and hence liable to
heel over in a gale of wind. And undoubtedly many gnats, particularly
in windy weather, are shipwrecked as soon as they emerge. This is, in
fact, a moment of peculiar danger to the little insect-mariner, and a
breath of untoward air will frequently drive it about like a ship in a
tempestuous ocean; and if it is once laid on its side, all is over with
the gnat; no patent apparatus can save it; and we have the mournful
testimony of Réaumur, that in stormy weather he has seen a vast number
of such shipwrecks in the mimic ocean of a pool of water. Generally
speaking, the peril is only momentary, and the insect emerges in
safety. Having thus raised itself to the perpendicular position, the
gnat withdraws its two forelegs from the pupa case, and stretches them
out; then it draws out its two next; and now feeling safe, it quits the
perpendicular position and bends toward the water, plants its feet on
its glistening surface, which is to it as safe as the land, since it
has the faculty of walking on the waves. It is now in perfect safety,
its wings expand and become dry, and presently the insect will for the
first time make use of them by flying to some adjoining twig.

[Illustration: _Blood-worms, natural size and magnified._]

But we need not in many cases leave our homes to see an escape from the
pupa in every respect as singular as the last, and in many, precisely
identical. Before the writer's study-window was an artificial fountain,
in which, as the water was not constantly allowed to play, aquatic
insects of various kinds had permission to establish themselves. Nor
were they long in availing themselves of this liberty. A week or two of
genial summer weather was sufficient to people the water with various
inhabitants among them was a little creature which will be recognised
by every reader when we mention its title--"the blood-worm." It is
in reality not a worm at all, although resembling worm in shape, and
in its serpent-like movements. This little creature was for a time
particularly active; and in a tumbler of water taken from the fountain
might be seen perhaps a dozen of them twisting about in a very singular
manner. By-and-by a change came over them, and it turned out that the
worm-like creatures had become pupæ of a blackish colour, thus at once
deciding their insect character. They belong, in fact, to the insect
called the _Chironomus plumosus_. These black pupæ were scarcely less
active than the red blood-worms, or larvæ of the same insect. They
flapped about their tails with great vehemence, and thus, although
their bodies naturally sink in the water, they were able to swim from
the bottom to the surface, or from side to side. Observing that they
had finished their appointed period in the pupa form, we became anxious
to watch their change into the perfect insect. Neglecting, however, to
notice them at the proper period,--the afternoon of a warm sunny day,
we were astonished the next morning to find a surprising number of pupa
skins lying empty of their tenants on the surface, as though some of
the water fairies enumerated in fable had been dancing on the waves all
night, and left their little black shoes behind them in their haste to
flee from the light of the smiling morning. We determined to be better
prepared for the observation on that day; and as the afternoon came we
had the gratification of seeing a large number of these insects rise
from the water, all in the following[Q] manner:--They rose up from
the bottom and reached the surface by the peculiar movement of their
tails just described; there the thorax was thrust above the water,
and immediately the insect burst its cerements, elevated itself by a
wave-like motion from the rest of the pupa-case, which filled with air,
and now glistened like silver; it then planted its forelegs on the
water, withdrew the rest of its body from the case, unfolded its wings,
and in a few moments was sailing in the thin air. On one stormy day the
surface of our fountain was bestrewn with the dead and dying bodies of
these insects drowned in the waves.

[Illustration: _Pupa and perfect Insect of the Chironomus Plumosus._]

De Geer,[R] speaking of the pupæ of a moth, states, that he was not
fortunate enough to witness the manner in which they quit their watery
abode. But he seems to think that they quit the pupa case, then mount
to the surface of the water, or up some aquatic plant, in order to
reach a dry spot, where they remain, their wings being developed
afterwards, and that thus the risk of their being wetted is avoided.
Their bodies being lighter than the water, he conceives, accounts for
their being able to rise to its surface. Too much weight, however, must
not be attached to this observation, as it is not accompanied with
satisfactory ocular evidence of the fact.

[Illustration: _Pupæ of Dragon-fly._]

[Illustration: _Pupa of Dragon-fly, showing the sharp points at the end
of its feet._]

The pupa of the "dragon-fly" furnishes us with a very interesting
example of escape; and it well deserves the reader's attention, if
he be so placed as to have the opportunity of observing it. Perhaps,
indeed, few insects afford us such a singular series of interesting
facts as are to be found in the escape of this one from its pupa. The
best method of observing their change is to procure as many of the
larvæ as possible, to put them in a basin of water, at the bottom of
which are a quantity of dead leaves, and to allow several sticks to be
in the water touching the bottom of the basin, and reaching above the
level of the water, as shown in the cut. Then we must watch carefully
to notice any of the larvæ which, having become pupæ, creep towards
the edge of the water. These are such as will in all probability be
the first to undergo the change, for they come to that position
in order that they may get dry before proceeding further. If these
are now closely observed, they will be seen after the lapse of a
little time to leave their position, and to begin creeping about in
search of a suitable spot where they may undergo their metamorphosis.
Most probably they will select for this purpose the sticks we have
introduced into the basin, and, after running up and down them, will
fix upon a particular spot, where they place themselves securely, the
head invariably uppermost. From what will be subsequently mentioned,
it is necessary that the insect should fasten itself so firmly to the
branch, that not even a violent effort would disturb its position. This
is secured by the insect thrusting the sharp claws with which its feet
are armed into the stem on which it rests. The points of these claws
are so fine and hard as even to penetrate wood with facility. They
are shown in the cut; and even after the dragon-fly has escaped out
of the pupa case, they may be easily made to fasten upon a piece of a
branch, by simply pressing the feet against it very lightly. In order
to watch the changes of this insect Réaumur once, whilst staying in the
country, collected a large number of the pupæ, and placed them on a
piece of cotton-print tapestry, where they soon felt at home, and fixed
themselves in preparation for their change, without moving far from
the spot where they had been placed. At few periods of the day could a
visit be paid to the room where this tapestry was hung without seeing a
spectacle at once diverting and extraordinary. Previous to its changes
the pupa becomes more transparent, and the large and beautiful eyes of
the insect it encloses grow increasingly brilliant. These signs always
indicate that the transformation is nigh at hand.

It comes to pass in the following manner:--Some movements of a
struggling kind take place inside the pupa case; and at length the
case splits at the upper part, near the head: through this rent the
body of the dragon-fly appears and tears it open, acting like a wedge,
until the slit extends along the head across to the two eyes. The
latter transverse slit is produced by a contrivance similar to that
mentioned in the case of the blow-fly, a sort of air bladder which the
insect distends at its pleasure, and thus causes the skin covering its
head and eyes to split open. The head and body of the insect rise and
make their appearance through the slit; and the head is now so much
larger than it appeared while in the pupa case, that it seems almost
impossible that it could ever have been contained within it. The insect
continues to rise perpendicularly out of the case, and the legs make
their exit, leaving the leg cases of the pupa undisturbed in their
attachment to the support on which it rests. In order to facilitate
the disengagement of the rest of its body the insect now bends itself
in a curved form backwards, being only kept from falling by the last
rings or segments of its body being still embraced by the sheath of
the pupa case. When it has extricated itself thus far, it begins to
move about its legs in different directions for several minutes, as if
to get them into use; but after this it ceases all movement whatever.
Not a quiver can be seen in its limbs, and the young observer would
be inclined to conclude,--as a great entomologist once did, the first
time he witnessed the changes of this insect,--that it was in reality
dead, and that it was a waste of time to watch it any longer. This
state of profound inaction may endure for a quarter, or even half an
hour: it appears to be intended in order to give time to the insect to
recruit its strength for a fresh and more violent series of efforts,
and to admit of its parts becoming hardened and dry. Suddenly, as we
are, perhaps, carelessly looking on the inanimate object, it performs
a feat of the most surprising, because unexpected agility. Its body,
which was previously much bent backwards, is now swung forwards and
bent into a curve; it then swings back, and then forwards again, and so
quickly that it almost seems to leap. It then rests its legs upon the
front part of the pupa case, and pulls the rest of its body out of the
case by degrees, and then creeps forward, leaving the pupa case behind,
still immovably fixed upon the plant.

[Illustration: EVENING FLIGHT OF EPHEMERÆ.

Page 269.]

"Behold," says Réaumur, "the dragon-fly new born, but very different
from those which traverse the air, or rest upon the plants around. It
is quite in disguise. The body, though longer than the pupa case out
of which it was drawn, has not got all its natural length. The wings,
which are the large and useful organs of these flies, have as yet
very little more volume than they had when enclosed in the short and
straitened pupa case. They are merely furrowed plates, or laminæ, of
some thickness, and arranged one over the other, as if packed together.
One can scarcely conceive how each of these wings can acquire its
proper dimensions,--how it is to enlarge and lengthen sufficiently.
They are folded into plaits like a fan, or like the leaf of a tree just
about to be developed; hence they naturally appear very narrow, and the
cause of their appearing so short is, that each of their longitudinal
portions is folded up like the paper lanterns, more frequently used by
nuns than by other persons."

The remaining portion of the dragon-fly's history will be found in the
next chapter.[S]

Some curious instances are given by various authors of the escape
of more than one insect from the same pupa. Thus we are told that a
male and female emperor moth were once produced from one larva, and
therefore one pupa, of extraordinary size. Messrs. Kirby and Spence
tell us of a German entomologist who says, that two specimens of the
pine-lappet moth were once produced from one pupa, which was of the
remarkable size of two inches in length and one in thickness. But these
are very rare instances, the common and almost universal rule being
that one pupa only contains one insect.

Nothing now remains for us to add to the insect's history in the pupa
state. Already,--for it is Spring far advanced,--the air is becoming
peopled with insect tribes--

    "The insect youth are on the wing,
    Eager to taste the honied spring,
      And float amid the liquid noon."

A thousand times ten thousand, nay, thousands of thousands, are already
in the air; and the low hum of their wings may be heard if we stand
breathless and listen in the midst of some sequestered spot, far from
the roar and bustle and strife of town life. But the great life-season
of the insect world is yet to come; and though May whispers it is nigh,
June, July, and August must bring it to us, and with it a teeming
multitude of insect flutterers more numerous than the stars of heaven,
or the sand-grains of the sea-shore.




PART IV.--THE IMAGO.




CHAPTER I.

THE NEW-BORN PERFECT INSECT.

    "Oh! start not! on thy closing eyes
      Another day shall still unfold;
    A sun of milder radiance rise;
      A happier age of joys untold.
    Shall the poor worm that shocks thy sight,
      The humblest form in nature's train,
    Thus rise in new-born lustre bright,
      And yet the emblem teach in vain?"


Beautiful as these lines are, and poetical as is the idea they develop,
they are incorrect. The perfect insect springing from the pupa is not
an emblem of man's glorious resurrection from this body of sin and
death; why, we shall immediately discuss. In the oftentimes beautiful
mythology of Greece, the name for the butterfly was [Greek: Psychê],
that the soul. Just as the insect bursts with brilliant wings from the
dull and grovelling form of the pupa, flutters in the blaze of day,
roams on untiring wings through the genial air, and enjoys the use of
faculties so new and strange to it, when contrasted with those of the
pupa state,--so was it imagined that the soul's arising from amid the
corruption of this vile body would prove a deliverance from the bondage
of mortality, and the countless infirmities to which it is heir. And
surely there was much poetry in the conception; but we, who must
not leave the path of true insect history for any poetical fancies,
have now to remind the reader that the simile is in many respects
inaccurate, and in so doing we shall merely bring to his recollection
what was said as to the contents of the pupa-case at p. 231. From this
it appears that the pupa state, far from being a state of death, is
one in which new parts are added to the insect; in which the insect is
actually not only alive, but in some instances capable of moving about,
as well as before or after; and, lastly, in which the various organs of
the perfect insect all exist previous to the disclosure of the latter.
Thus, if we were to slit open a pupa-case just before the insect bursts
from it, we should find that, although kept in bondage by the case,
the insect was in all respects the same as if we had allowed it to
break out of its prison in the ordinary manner. In a word, the perfect
insect is after all only the same being which we saw in the egg, larva,
and pupa states, now having cast off its last skin, and become an adult
being.

When a man or an animal dies, the particles of the body are separated
from each other, their union is destroyed, and they themselves are
dissipated in various ways. The flesh returns to dust, the spirit to
God who gave it. How different this change from that which the insect
undergoes! and how inappropriate in strictness, as

    "Emblems of our own great resurrection,
    Emblems of the bright and better land,"

as emblems of the mysterious union of the immortal soul and its
immortal, incorruptible body! The fable of the Phoenix was more
expressive of the real nature of this great change; for there the body
of the creature was reduced to death first, and the new-born being
sprang from its ashes. As we are anxious to convey only the most clear
and accurate idea to the reader's mind of the various stages of insect
life through which we are conducting him, it appeared expedient to
notice the mistake taught in these pleasing lines, only to avoid the
error of its being supposed that they give us an accurate idea of the
true nature of the change from pupa to _imago_.

The term _Imago_ is a Latin word, and, like those of _larva_ and
_pupa_, was given to insects in this condition by the naturalist
Linnæus. It signifies properly an image, copy, or representation of any
object. In applying it to insects in their last stage, Linnæus intended
that we should understand by it, that the insect had now reached its
stage of perfection, and had become in all respects exactly like, that
is, _the image_ of, its parent. And though a better term might probably
be found, yet as no person is likely to fall into any serious mistake
merely because we call an insect in its last state an _imago_, it is as
well to retain it; better indeed, than, by inventing another, to create
nothing but confusion and disorder in the minds of young entomologists.
In this chapter, therefore,--the last chapter of the Life of an Insect,
the word _imago_ may be considered as synonymous, or having the same
meaning, with that of "perfect insect;" it is an insect's last stage of
existence.

It would be a great mistake to suppose that the insect, so soon as
it leaves the pupa-case, is in that instant in every respect similar
to what is known to us as the perfect insect. When, for example, a
butterfly has just succeeded in extricating itself from its pupa-case,
if we were to take it up in the expectation of finding it all at once
decked with the glories of its wings, and elegant in its form, we
should be disappointed. Owing to the cramped position which its limbs,
and wings, and other organs, have so long been made to occupy, its
appearance when it emerges from the pupa is necessarily different from
that which it wears after all its limbs have been in free exercise, and
the flutter of its wings has been heard over hill and dale, throwing
the gentle air into an irregular line of tumult.

Now that summer has come, abundant opportunities for watching insects
in all their stages may be had; and by careful searching of the garden,
field, and woodland, a number of pupæ may be discovered on the very
eve of disclosing the imago, or perfect insect. Let us suppose that
the reader has not looked in vain; but has brought home in a tin box
several of these singular objects, about which so much has been said.
The pupa, ready to burst open and let loose the struggling captive
within, is before him; the skin splits, the body of the insect appears,
withdraws itself from the pupa-case and inner membranes, and the imago
appears before him. But O, how different from the splendidly adorned
insect which we know it is still to become! Its tender body is weak,
soft, and languid, and bedewed with moisture. Its wings, instead
of being of their usual size, and variegated with such glowing and
admirably contrasted colours as only a Divine hand could create, are
in the largest sized butterflies scarcely bigger than the nail of the
little finger; instead of being uplifted in full strength and beauty,
they hang drooping down over the sides of the trunk; and their colours
are all dull, and muddy, and without any of those distinct spots and
beautifully defined marks, streaks, and bands, which we observe with so
much admiration in the wings of these insects. Altogether we might take
it rather for a mutilated and imperfect insect, instead of what, in
spite of its unattractive appearance, it really is,--a perfect insect,
and in a short time to become a splendid one.

We have only to wait patiently for the lapse of a little time, and
our desires will be fully gratified in beholding all these symptoms
of weakness and imperfection disappear. The imago, attaching itself
either to the cast-off pupa-case, or to some other convenient support,
first stretches out one organ, and then another; its body loses the
coating of moisture which bedewed it, its various parts become firm and
hardened, and its colours come forth in all their beauty. All the parts
which had been forced into a constrained position, now relieved, assume
that which is natural to them in the perfect insect; and the wings no
longer have a questionable appearance, but become expanded into those
light and exquisite structures which form the peculiar beauty and
characteristic of many insects, displaying themselves almost magically
in the form, it may be, of the thin, transparent membrane of the fly,
or as the painted tissue of the moth or butterfly, extending frequently
to five or six times their previous dimensions.

Here let us take up, as an illustration of these beautiful and
interesting phenomena, the concluding portion of the history of the
dragon-fly, commenced at p. 302. The expansion of the wings of this
elegant creature, after it has left the pupa-case, and fixed itself,
generally on the stem of some pond plant, goes on so rapidly, that we
can actually see them becoming larger each moment as we look upon them.
If we were to attempt to trace their outline on paper, before the next
stroke could be added, their form would be different. During the whole
time that the development of the wings goes on, the insect continues
perfectly still and immovable. Its wings are not stirred in the least,
and the insect seems to avoid all risk of having these delicate organs
touched by any surrounding object. Its wings, which are by-and-by to
possess almost the stiffness of a thin layer of the mineral _talc_,
are at present softer and more flexible than wet writing paper, and if
they were to receive any injury while in this condition, that injury
could never be repaired; hence the insect requires to be in a perfectly
quiet condition. The dragon-fly seems to be fully aware of this, and
in order to prevent the wings, as they increase in size, from drooping
down towards, and coming in contact with, its body, it curves it in the
manner represented, so as to allow for the expansion and elongation of
the wings. At length, generally in a quarter of an hour's time, their
development is fully completed; but they are not yet sufficiently firm
and resisting to use in flying. If left to itself, the insect generally
waits three, or even four hours, before it puts them into inactivity.
In addition to the expansion and elongation of its wings, its body
also elongates, until it has acquired its full dimensions. In vain
should we look at first for the splendid colours in which these insects
are decked; all the tints are blotted and unpleasing. Those charming
species, which are spotted with beautiful blue and yellow tints
intersprinkled with black, are, when they are but just emerged from
the pupa, of a whitish yellow spotted with brown; the yellow marks,
however, are seen to change to a beautiful deep orange, the brown to
black, and some of the yellow marks to blue.

The following interesting description of the same changes as they take
place in the butterfly is from the valuable work of Messrs. Kirby and
Spence. "The pupa of a very interesting and beautiful butterfly, the
only one of its description that Britain has yet been ascertained to
produce, I mean _Papilio Machaon_, being brought to me by a friend
early in May, this year, on the sixteenth of that month I had the
pleasure of seeing it leave its pupa-case. With great care I placed
it upon my arm, where it kept pacing about for the space of more than
an hour, when all its parts appearing consolidated and developed, and
the animal perfect in beauty, I secured it, though not without great
reluctance, for my cabinet, it being the only living specimen of this
fine fly I had ever seen. To observe how gradual, and yet how rapid
was the development of the parts and organs, and particularly of the
wings, and the perfect coming forth of the colours and spots, as the
sun gave vigour to it, was a most interesting spectacle. At first it
was unable to elevate or even to move its wings; but in proportion as
the aërial or other fluid was forced by the motions of its trunk into
their nervures, their numerous corrugations and folds gradually yielded
to the action, till they had gained their greatest extent, and the film
between all the nervures became tense. The ocelli, and spots, and bars,
which appeared at first as but germs or rudiments of what they were
to be, grew with the growing wing, and shone forth upon its complete
expansion in full magnitude and beauty."

If we were expert anatomists, and were armed with a good microscope,
the study of the wing of a dragon-fly would prove one of great interest
to us. These beautiful organs, however, must be examined when they are
as yet but a little expanded, as in their completely developed state
we should certainly fail in detecting their real structure. Thin and
gauze-like as they seem, they are in reality double, consisting of
an upper and a lower surface, between which are several parts which
are necessary to preserve the shape and carry on the functions of
the wings. The two surfaces of the wing enclose what are called the
_nervures_, resembling in some respects the veins of a leaf. These
are really fine hollow tubes of some firmness, which ramify in large
numbers between the two membranes of the wing, and thus give strength
and stability of figure to them. Along these tubes, or nervures,
branches of the air-vessels, or _tracheæ_, and of the blood-vessels,
run.

From these necessary details let us turn to make the difficult, but
important inquiry--How are the wings expanded? by what means do
they, from being thick, soft, and moist, become thin, hard, and dry?
It is to be regretted that this inquiry cannot be answered with that
satisfactory certainty which it deserves. It is very difficult to
catch the insects in which the expansion of the wings is best observed
at the right moment; and even then it is extremely difficult to say
whether one cause more than another may contribute to this phenomenon.
The following explanation of it is given by Messrs. Kirby and Spence,
whose general accuracy on such subjects is well known. "As soon as the
insect is disclosed, a fluid enters the tubes or nervures, and being
impelled into their minutest ramifications, necessarily expands their
folds; for the nervures themselves are folded, and as they gradually
extend in length with them, the moist membranes attached to them are
also unfolded and extended. In proportion as this takes place, the
expanding membranes approach each other, and at last, being dried by
the action of the atmosphere, become one. To promote this motion of
the fluid seems the object of the agitations which, in many instances,
the animal from time to time gives to its unexpanded wings. That a
kind of circulation, or rather an injection of an aqueous fluid into
these organs, actually takes place, may be ascertained by a very simple
experiment. If you clip the wings of a butterfly during the process
of expansion, you will see that the nervures are not only hollow,
but that, however dry and empty they may subsequently be found, they
at that time actually contain such a fluid. Swammerdam, who appears
to have been the first physiologist that paid attention to this
subject, was of opinion, that an aëriform as well as an aquiform fluid
contributes to produce the effect we are considering. He had observed
that if a small portion be cut off from the wing of a bee, a fluid
of the latter kind exuded from its vessels in the form of pellucid
globules, becoming insensibly drops, which he concluded proved the
action of the latter; and he noticed also that the wings were furnished
with _tracheæ_, which were at that time distended by the injected air;
whence he justly surmised, that the action of the _air_ was also of
great importance to produce the expansion of the wing." But Swammerdam
appears only twice to have seen the expansion of the dragon-fly, in
which this phenomenon is best observed. Herold, an eminent naturalist,
also attributes the expansion of the wing to the flow of an aqueous
fluid into the nervures. M. Chabrier, a French entomologist, having
observed a fluid in the interior of the nervures of the wings of
insects, thinks it probable that they can introduce it into them and
withdraw it at their pleasure, so as to facilitate their unfolding.
When we call to mind the force with which the blow-fly, or flesh-fly,
and the dragon-fly, are able to expand their heads by forcing air into
them, we need scarcely ask for any other explanation than simply that
the tracheæ are distended with air, and by that means the soft and
yielding wings are made to assume their distended state.

It has been mentioned, that, in the case of the dragon-fly, the
completion of the unfolding of its wings occupies about a quarter of
an hour, but that sometimes it is even half an hour. The ordinary
period is from five to ten or fifteen minutes in most insects, but
it is sometimes prolonged to an hour, or to several hours. Again, in
others, as we have already seen in the history of the emergence of the
gnat, and other insects, from their aquatic state in the pupa, it is
completed in a few seconds, and the insect only rests for this brief
period on the surface of the water, previous to taking flight from its
apparently somewhat dangerous position.

Some observations of Mr. Rennie show, in a singular manner, the fact
before mentioned, that if the wings, while yet wet and soft, are in
any way pressed upon, or otherwise injured, they will never assume
their proper appearance. "The thread by which a chrysalis is suspended
may sometimes snap asunder; when this happens, and the chrysalis is
allowed to remain, it will not usually produce an insect complete in
all its parts; for the side upon which it lies being pressed against
an unyielding substance by its own weight, instead of hanging lightly
suspended by a silken cord, is prevented from becoming duly expanded,
and when the insect is excluded, it is found to be deformed. A colony
of the brown-tail moth, which we reared during the summer of 1829,
spun in the corner of a nurse-box, a common web of several chambers
for containing the pupæ. One of these chambers being accidentally
torn, a pupa fell upon the earth in the bottom of the box, and in due
time, a female moth was produced from it; but she never succeeded in
expanding her wings, which remained till her death, shrunk, rumpled,
and totally useless for the purpose of flying, though in every other
respect she was full grown, and deposited in the box a group of fertile
eggs, covered with down from her tail, as neatly as was done by her
sisters of the same brood. In the summer of 1825, the chrysalis of
a small tortoise-shell butterfly, (_Vanessa urticæ_,) lost its hold
of its silken suspensory, and fell upon the pasteboard bottom of a
nurse-box, resting in a sort of angular position, so that the case
of the upper wing on the left side, pressed upon the box with the
whole weight of the chrysalis above it. When the butterfly made its
appearance, it expanded its wings as usual; but the wing upon which
it had rested was not half the size of the one on the right side
which had lain uppermost. Another of the same brood had, from some
cause, not grown so large in the caterpillar state as the rest. It was
transformed, notwithstanding, into a chrysalis, which appeared healthy
and well-formed; but when the butterfly appeared, though it did not
differ from the usual appearance, its wings never expanded a single
hair's breadth, and remained always in the same state as when it issued
from the chrysalis."

After the insect has once withdrawn itself from the pupa-case, it
generally retains the same appearance and raiment as long as it lives,
not casting its skin like the larva, but having put on its permanent
clothing immediately upon its leaving the pupa-case. But in the case of
an aquatic insect, the _Ephemera_, of which we have before spoken, a
remarkable exception to this rule has been noticed. When these insects
leave the pupa-case, any one, on looking at them, would say that they
had completed their changes; they appear to be furnished with every
part necessary to them, and not to have any which is redundant; yet
they are destined to go through a change equivalent to that which has
just taken place, if, indeed, it is not more apparently difficult than
it, and that is,--they have to cast off their skin. That they should be
able to withdraw from thence their head, their legs, their body, and
their long tails, would be no great difficulty for us to comprehend,
because numbers of insects at their escape from the pupa-case do more
than this; but in their case we are presented with a more perplexing
enigma. In the transformation of other insects, as we have already
seen, and, indeed, in that of the insects before us, the wings are at
first very soft and pliable, and therefore can be easily withdrawn
from the cases in which they were contained. But in the _Ephemera_,
the wings, after it has left the pupa-case, are fully developed and
expanded, and seem to have acquired all their consistence, and to have
become hard and inflexible. Moreover, its wings are so thin, that we
can scarcely believe that they are in reality double; that is, that
they are covered by an outside sheath; and it seems incomprehensible
how, if such is the fact, the wings can be withdrawn from this case or
sheath, when the only opening that can be discovered for that purpose,
is a very minute hole near the spot where the wings take origin from
the body of the insect. Let us now see how all these difficulties are
overcome, and how the insect withdraws itself from this, as we might
almost call it, second pupa-case.

[Illustration: _Dance of the Ephemeræ._]

The Ephemeræ, when they leave the water, rise high into the air, and
wing their way perhaps far from the place of their birth. They may
often be found wheeling over green fields, or wandering among the
forest shades, far from the bubbling stream in whose waters so large
a portion of their existence was spent; but more frequently they are
to be found somewhere in the neighbourhood of the stream, enjoying an
aërial dance. The feet of the insect are armed with hooks of great
minuteness, and by their means the insect attaches itself to a suitable
object, sometimes to a wall, sometimes to a twig, or to the trunk of a
tree; it does not much matter where. Without at first making the least
movement, the insect patiently abides the time when it must withdraw
itself from its useless upper garment, and sometimes it has to wait a
whole day in this position. The time arrived, the skin splits, and the
body of the insect rises gradually out of it; but the difficulty is
about the wings. Nevertheless, as we watch the insect, we shall find
that it gradually draws them out of their delicate cases, and at length
emerges, as perfect in beauty and form as before. The manner in which
this is effected is as follows:--although the outer case of the wings
is hard and rigid, yet the wings which it covers over are preserved in
a soft and moist condition. In proportion, therefore, as the insect
disengages itself from the anterior part of the skin, the inner or real
wings become contracted, by a number of plaits, into a form nearly
cylindrical, which readily admits of their being pulled through the
openings lately mentioned; and as soon as the insect is released from
its envelope, these plaits unfold, and the wings return to their former
shape and dimensions. So exactly does this thin skin, thus cast off,
fit all the parts of the insect's body, that it may often be mistaken
for the insect itself, when it is found clinging to the place where it
has gone through its changes.

[Illustration: _Wingless Beetle._]

Before we leave the subject of the wings, it must be mentioned that
there are some insects which have none. The cut represents a beetle of
this class.

If the reader will now take a peep into one of the nurse-boxes in
which he may have been rearing butterflies from the pupæ, presuming
that several of them have ere this burst from their cases, and are
fluttering about anxious for liberty, he will generally detect upon
the bottom or sides of the box one or two marks of a somewhat reddish
colour; sometimes, indeed, they are very red. These spots are produced
by the insect, which, on its emergence from the pupa, generally
deposits a drop of fluid from its intestines. Almost all insects
perform the same action at this period; but we may well remark with
Réaumur, it could scarcely have been supposed, that the excrements of
a butterfly should ever have filled the minds of a whole population
with terror. Such has, however, been the case, and may, perhaps, yet
be in districts where ignorance and superstition close the minds of
the inhabitants against the truths of entomology. "Historians," says
Réaumur, "tell us of showers of blood, as having been the cause of
terror to nations, and considered as prophetic of fearful events,
of the destruction of cities, and revolutions of kingdoms. At the
beginning of the month of July, in the year 1608, one of these showers
of blood was said to have fallen in the suburbs of Aix, and for some
miles around. It turned out that the supposed drops of blood were
in reality drops deposited by the butterflies. It is not improbable
that other showers of blood recorded by historians, and taking place
about the same period of the year, might be accounted for in the same
natural and simple manner. Gregory of Tours relates that in the time
of Childebert a shower of blood fell in different places in Paris, and
particularly in a certain house situated in the territory of Senlis.
Another was said to have fallen toward the end of June, in the reign
of King Robert. In the year 1533, we are told by another author, a
prodigious multitude of butterflies appeared throughout a great portion
of Germany, sprinkling plants, leaves, buildings, clothes, and men,
with bloody drops, as if it had rained blood."

In the Gentleman's Magazine for the year 1764 we read that "a kind
of rain of a red colour, resembling blood, fell in many parts of the
Duchy of Cleves, and caused great consternation. Something of the like
kind fell also at Rhenen, in the province of Utrecht." A gentleman is
reported to have sent a bottle full of it to Dr. Schutte, to know if it
contained anything pernicious to health. Dr. Schutte wrote a learned
dissertation upon it, and gave it as his opinion that it was caused by
the particles which had been raised into the atmosphere by a strong
wind, and that it was in no way hurtful to mankind or beasts. Probably
butterflies were the real shedders of this blood-like shower, as in the
previous cases.[T]

Our next remark about the imago state of insects will, perhaps, create
some surprise--Insects in this state, with some apparent exceptions,
_do not grow larger_. When they leave the pupa state, and have all
their parts fully developed, they do not subsequently increase in size.
We are often told by ignorant people that the little house-flies which
we watch dancing in our chambers, or scrambling up our windows, are
only young flies of the same kind as flesh-flies, and that by-and-by
they will grow into a large "Blue-bottle!" This is a sad mistake. Let
the reader try. Let a fly be put under a glass, and fed with a little
sugar, or honey: in vain will he daily examine it, in the expectation
of beholding it increase in size--it will live and die nearly the same
little being unaltered to the last. If such persons only knew somewhat
of the life of an insect, such an absurd, and, unfortunately, very
prevalent mistake would not be committed. We might as reasonably call
a trout a young salmon! If we were to examine any number of flies of
the house-fly kind, (_Musca domestica_,) and carefully measure them, or
weigh them, we should find them all almost exactly of the same size;
which, of course would not be the case if they really grew larger as
they grew older.

But there are some insects which, after they leave their pupa, increase
within a very short time to a size which could scarcely be believed.
In particular, the new-born insects of a tribe of flies which produce
the aphis-lion larva before spoken of, are distinguished by this
peculiarity. We behold a very little insect emerge from the pupa-case,
and in a quarter of an hour we are astonished to find it has grown
to a great fly! This sudden increase appears the more marvellous,
because during this period the insect takes no nourishment. The wings
of this insect, when it is just born, are not more than _one-tenth_
the size they acquire in that short space of time. The insect is to
all appearance firm and plump, and offers a ridiculous contrast to the
tiny pupa-case out of which it has emerged. It appears probable that
this sudden enlargement is to be accounted for by the insect filling
itself with air, and thus causing the various parts so closely packed
together, and fitted into one another, in the pupa, to be expanded.
The experiment which puts this idea to the test is a very simple one;
we need only prick the body of the insect with a fine needle, and we
shall hear a slight sound produced by the escape of the air; and in a
few seconds the body of the creature shrinks to its former dimensions.
It appears, indeed, that the body of the insect is actually larger at
this time than at a subsequent period of its life, when it becomes
more flattened and shorter. Another beautiful insect, one of the
lace-winged flies, exhibits the same singular phenomenon. Its pupa-case
is not larger than a small pea, yet the body of the insect is nearly
half-an-inch long, and covers, when its wings and antennæ are expanded,
a surface of an inch square. It appears, in fact, almost incredible
that it could ever have been contained within so small a compass.

The cases just related may appear to be really exceptions to the rule
just laid down, as to the non-increase of insects when once emerged
from the pupa; but upon a little consideration it will be found that
the exceptions are more apparent than real. The increase in size is not
really a process of _growth_, but is simply owing to the expansion of
the body of the insect to its due size, only taking place in a sudden
manner by breathing a certain amount of air. The dragon-fly gives
us another instance of a similar enlargement soon after leaving the
pupa-case.




CHAPTER II.

THE STRUCTURE AND ORGANS OF THE IMAGO.


[Illustration: _White Hawthorn Butterfly._]

We must now ask the reader's attention to a very important part of the
history of the insect--the knowledge of its various parts, and their
uses in the insect economy. Men of science would call this the anatomy
and physiology of insects; and if there is a desire felt to know and
retain the proper terms employed by those versed in this science when
they treat of these subjects, it will be well to bear these names in
mind. We may, however, convey some notion of the nature of the studies
called by these names, by the following illustration. Let us take
yonder butterfly as our example, and, arresting it in its zig-zag
career over flowers and fields, let us carefully bring it in-doors,
and there look closely at its various parts and appendages. There we
find two long, delicate, thread-like organs springing from the head;
then we come to the head, with its different organs; farther back is a
separate portion, distinct from the head, and distinct, also, from the
remainder of the body of the insect; at the side of it are the wings;
below are the legs; last of all we bring under our notice the remaining
division of the insect's body, the abdomen. Now if Anatomy stood at our
right hand while we took notice of each part, she would point out all
the peculiarities of its structure, and would tell us of how many other
parts it was made up, and how all were beautifully and wonderfully put
together by the skill of the Great Creator. Further than this, she
would, very probably, strongly insist upon our remembering each part by
a particular name; and, as we may add, since she is particularly fond
of, and learned in, Latin and Greek, we may rest quite assured each
name she communicated to us would be in one or other of these classical
languages; for example, instead of saying the butterfly was one of the
"_scale-winged_" insects, which would be far too homely for her, she
would declare that it belonged to the _Lepidoptera_, which is the same
thing in Greek; and its "head" she would inform us was the "_caput_,"
which is the Latin for that word! This done, her strict duties would be
exactly fulfilled, and she would summon her sister-science, Physiology,
to give us further information about the butterfly. Physiology, who,
we may remark, is a far less stern-looking personage than her austere
relative, and appears with a countenance which expresses that she has
much to tell us which will greatly interest us, would next take up the
panting insect. She would tell us to consider attentively the head of
the little creature, while we listened to her elegant account of the
purposes it was intended to subserve. She would dilate with eloquence
upon the exquisite machinery which was compacted into so small a
compass as its mouth; and she would render us almost breathless with
amazement, as with rising animation she revealed to us the astonishing
optical wonders of an insect's eye, telling us, perhaps, that an insect
may probably see like the fabled Argus, behind, and before, and on
every side, at the same time! Then she would tell us, in order, the
nature and uses of each part, and, in a word, give us a minute, but
delightful account of everything that is known about the Life of an
Insect.

From this it will be manifest that we have hitherto chiefly listened
to the voice of Physiology in this little book, although the leading
particulars of the Anatomy of the insect in its various stages have
also been brought before us. We must now address ourselves for some
little time to learn, from the combined sciences of Anatomy and
Physiology, the structure and uses of the different organs, and their
principal parts, in the insect, in the _imago_ or perfect state. In
order to follow the account we shall have to give the reader, it will
be convenient to take some common insect, such as a _wasp_, and fix in
the memory the names of the various parts we shall have to distinguish,
in thus treating of the _imago_-insect. A dragon-fly is a good example
also. We shall first mention the general arrangement of the insect's
structure; and subsequently take up each part separately.

It must first be mentioned, that insects possess no _internal_ bony
skeleton, like that possessed by ourselves and many other animals.
If we were to cut open the dead body of a fly, we should look in
vain for anything like the back-bone, or the bones of the legs. But
it must not, therefore, be thought that insects have no skeleton at
all. Their skeleton is the thick, hard, horny substance which forms
their external covering. In the wasp, for instance, it will be easily
perceived, on pressing the head or the trunk of the insect between
the fingers, that there is a very firm, solid coating, protecting the
tender and delicate organs within. It is a very singular fact that the
wisdom of the Creator has so ordered this outside coating, that where
it is most necessary to be strong, as for example, when an insect has
to burrow through the ground, or is in danger of being often crushed,
there its thickness is greatest; and again where, as in the case of
those insects which live chiefly in the air, this thickening is less
necessary, because there is less risk of injury to its body, there the
external covering is thinner and softer. So extraordinarily is one
insect strengthened in its external coats, that it is scarcely possible
to crush it by the hardest squeezing between the thumb and fingers. It
has, on this account, been compared to a once famous London character,
called "_Leather-coated Jack_," who used to suffer carriages to be
driven over his body without receiving any harm!

In looking at an insect, we perceive that it is naturally divisible
into three principal parts: first, there is the head, or _caput_; next,
the trunk, or _thorax_; and thirdly, the hinder portion of the body,
or _abdomen_. If we turn to a Latin dictionary, and hunt out the word
_insecta_, which is the Latin term for "insect," we shall find that it
is derived from a verb which signifies "to be cut in," or "notched."
From this we see that the very word _insect_ has arisen from perceiving
what we are now alluding to, the natural notching of the body of these
creatures into certain portions. We mentioned, however, at page 89,
that the insect in the _larva_ form had a body which was, in almost
every instance, divided into _thirteen_ segments, or parts. It may be
asked, Are these all lost in the perfect insect; or are they still to
be traced in it? They are still to be traced in it. The head is one,
three form the trunk or thorax, and the remaining number constitute
the abdomen: but, in order to save disappointment, it must be added,
that it is rare to find the full number of segments or distinct parts
in the abdomen; we seldom, in fact, find more than seven or eight,
the remaining two or one being generally hidden. It is interesting,
however, to trace in the perfect insect these indications of its
previous larval condition, especially when we remember the strange
appearance it underwent while a pupa.

Now the various parts in the _head_ division are, to speak generally,
the _head proper_, the _mouth_, the _eyes_, and the _antennæ_.
Entomologists describe a large number of other parts, which would also
be mentioned here if this little treatise were intended to give a
minute account of the insect's anatomy; and those features which are of
most prominence and importance, will be mentioned in addition when we
come to speak particularly of these several chief organs.

The middle portion of the insect, or _thorax_, is divided into three
parts--a front, middle, and hinder part; or, in the language of
entomology, a _pro-thorax_, a _meso-thorax_, and a _meta-thorax_.
Attached to the thorax are the _wings_ and the _legs_. The remaining
portion, or _abdomen_, is furnished with organs and appendages, not
requiring special mention in this place.

[Illustration: _Eyes of a Bee._]

Let us consider briefly the organs which are seated in these divisions;
and, beginning with the head, let us glean a few particulars upon that
most interesting topic--the eyes of insects. We might well fill a
volume with this subject alone, for truly it is almost inexhaustible.
In the other sections of the animal kingdom, the eyes, though organs of
the highest importance, are, nevertheless, simple, and little varied
in their number and arrangement. But in insects, whether we consider
their number, their structure, their arrangement, or their size, we
are lost in amazement at finding these organs assume an importance in
the insect's economy, of which we have no parallel elsewhere. Look,
for example, at the accompanying representation of the eyes of a bee,
and then let us ask whether, in all the world beside, we can find a
creature whose two eyes are larger than all the rest of its head put
together? What should we think of a quadruped as large as a bull, whose
eyes occupied great part of its head, its forehead, and the greater
portion of its face? What astonishing powers of sight it would possess!

[Illustration]

The first thing we learn about them is, that some insects possess what
are called _simple eyes_, and _compound eyes_. The accompanying cut
represents in part the head of a _flea_, and is annexed in order to
give a specimen of a _simple_ eye. The little circle represents the
position of the simple eye. All the organs connected with the head
are supposed to be cut off. The head of the bee on the preceding page
furnishes us with an excellent illustration of a _compound eye_. All
perfect insects are provided with compound eyes, and a large number
with simple eyes too; but no imago or perfect insect has simple eyes
alone. We see, therefore, that the simple eyes are only additional or
supplementary organs to the compound eyes, which are the chief organs
of sight in these creatures. These simple eyes are minute lenses
generally placed upon the crown of the head, or the forehead; in the
bee this is their position; and by means of a pocket-glass, they can
be readily seen in this insect, by looking at its head from above.
They will be found arranged in a triangular form. Sometimes an insect
is furnished with as many as sixteen of these simple eyes; the spider
is, among others, thus endowed. But more commonly they are only three
in number. Sometimes they are not imbedded in the substance of the
head, as might be supposed; but are actually placed upon the end of a
little stalk, presenting an appearance as singular, as if at the end
of a bull's horn the animal were to possess an eye in addition to his
two others. Swammerdam and Réaumur performed some singular experiments
upon these eyes in the bee. Réaumur varnished the back of the head,
where these eyes are situated, in more than twenty bees, so as, of
course, entirely to blind these eyes; but leaving the large compound
eye untouched. The bees were then set at liberty within a few paces
from the hive, but not one of them knew where to find it again! nor,
indeed, did they appear to make any search for it. They flew at random
to the adjacent plants, but never to a distance; and though they seemed
to have no difficulty in flying, they did not attempt to fly up into
the air.

[Illustration: _Eye on a stalk._]

[Illustration: _Eye of the Dragon-Fly._]

The compound eyes of insects are, perhaps, among the most wonderful
works of the Creator's hands. In those gigantic creatures whose
fossilized bones are all now remaining to tell us of their history,
the _mastodon_, and _megatherium_, and in such vast creatures as the
elephant and the whale, we behold the great power, skill, and wisdom
of God; but here, in a little object which we may cover with a pin's
head or with a large grain of sand, is a more wonderful instance of His
infinite and amazing power than all these. The eye of a dragon-fly is
a good instance of a compound eye: and of all the beautiful, radiant,
gem-like objects that can be selected for inspection through the
microscope, this is the most exquisite. Professor Müller, the great
German physiologist, has with wonderful patience and care dissected
the eye of this insect, and has given a most beautiful account of its
structure. On examining the eye of this insect, even with a good pocket
magnifying glass, such as those commonly sold by opticians for a few
shillings, it will be found to present the appearance of a beautiful
net-work, or very fine grating, as is shown in the cut. When a greater
magnifying power is employed, it will be seen that each space in this
net-work is a six-sided or _hexagonal_ figure. Now each of these
little spaces is filled by a beautiful minute lens of the same shape
set in it. On making a perpendicular cut into the eye it has been found
to consist of various layers: the outer layer is a hard clear membrane
composed of a multitude of six-sided facets, each forming a more or
less distinct cone-shaped cylinder, which runs towards the centre of
the eye, as seen in the cut. Under this is a layer of coloured matter,
sometimes of a violet, or green, or even reddish hue, which is pierced
with as many holes as there are facets. Beneath this there is a varnish
of a black colour, within which is a second layer of coloured matter;
and in the space between this last and the first coloured layer the
delicate fibres of the nerve of sight, or optic nerve, run. These
fibres then converge together at the back of the eye into a single
large nerve, which is connected with the insect's brain, and conveys
the impression of sight to that organ.

[Illustration: _Magnified section of the Eye and its nerve._]

[Illustration: _Magnified section of part of the Eye._]

Perhaps this account may be followed with some difficulty; let us,
therefore, take a single facet, and trace it to its termination. Each
facet being in fact a distinct eye, we shall be able, in so doing, to
get a clear comprehension of the whole organ, which is after all only
made up of a large number of these distinct eyes. Separating, then,
one facet from the rest, we find this single eye to consist of several
portions: 1. the six-sided facet; 2. the cone-shaped cylinder, clear
and transparent; 3. a delicate fibre of nerve connected with the bottom
of this cone; and, 4. the large nerve itself. The diagram on the next
page will make this perfectly intelligible.

But it may be asked, What of the colouring matter? It exists in three
places. 1. The first layer surrounds the cones (2), and separates them
from one another, and from the nerve below in part. 2. The second
layer surrounds the nerve fibres (3). And, 3. the last layer is at the
junction of the nerve fibre (3) with the nerve itself (4).

This apparently complicated mechanism well deserves the reader's
attention; nor should the subject be quitted until it is clearly
understood. We are unable to enter into further particulars upon
the structure and functions of this beautiful apparatus; but it must
be added, that the following is the manner in which the ray of light
becomes perceived by the insect. It first passes through the facet
(_a_), next enters the cone (_b_), then strikes upon the nerve (_c_)
which conveys the impression, taking the large nerve (_d_) to the
brain. The colouring layers are intended to prevent any rays of light
from passing to other parts of the insect's eye, and so confusing the
impressions made upon its senses by external objects.

[Illustration: _A single facet separated, and magnified._]

The number of these facets, or, if we choose to call them so, distinct
eyes, varies in different insects. In some there are comparatively few,
in others an amazing multitude. The following list of their number is
given by Müller, as observed by various entomologists:--

  In the Ant there are          50
    "    Convolvulus Sphinx  1,300
    "    Common House-fly    4,000
    "    Silk-worm Moth      6,236
    "    Goat Moth          11,300

  In the Dragon-fly         12,544
    "    Butterfly          17,355
    "    Mordella           25,088

According to the calculations of another author there cannot be fewer
than 34,650 in the compound eye of a butterfly. Amazing thought! each
of this immense host is considered to be a separate eye, receives
separate impressions of light, and has a separate structure and
organization, both perfect in their kind.

It is not difficult to remove the compound eye of an insect; and in
so doing it will be found that each lens is as clear as crystal. The
ingenious Réaumur actually succeeded in removing one and adjusting it
to a lens; and he found that he could see through the insect's eye
very distinctly, only he says the surrounding objects appeared to be
greatly multiplied. There is a common optical toy which is ground into
a number of facets which communicates this appearance to objects when
seen through it, and thus furnishes us with a good illustration of the
endless confusion of images which would have perplexed the insect, had
not the various beautiful contrivances of which we have spoken been
adjusted to prevent it.

But we must guard against a very natural mistake which might arise upon
the subject of the eyes of insects from supposing them in any degree
comparable to those of higher animals as regards their motions. When
man, or an animal, wishes to look at any object, they do so by causing
several muscles to be brought into action which move the eyes round so
as to receive the rays of light from the particular point where this
object is placed; and so admirably arranged is the mechanism by which
these movements are effected, that they are as well provided for all
the purposes of sight with two eyes as with twenty. In insects no such
apparatus exists; the eyes are quite immovable; they are, in fact, set
in the head like a gem in a lady's ring, and are altogether removed
from the control of the insect. In order to obviate the annoyance and
inconvenience which would result from this arrangement, their eyes are
formed on the wonderful principles already mentioned, and, instead of
insects being furnished with two eyes, they are provided with many
thousands! They are thus enabled to enjoy not only the same extent and
range of vision with ourselves, but even a much larger.

Insects are also furnished with a contrivance by which they can see
objects at a little distance, and objects at a great distance--it
may be at the same time; which is more than can be strictly said of
ourselves. In men and animals there is a very exquisite apparatus
arranged within the eye, by means of which it can accommodate itself to
objects close at hand, or again to others at the greatest distance. We
can see at one moment a pin at our feet, and at the next the summit of
a hill some thirty or forty miles off. Now the laws of light are such,
that, to effect this properly, we must have some apparatus in the eye
to arrange its focal capacity, so as to receive and concentrate the
lines of light proceeding from such different points as the distance of
a few inches, and that of many miles. What this apparatus may be is not
as yet very satisfactorily determined. But in insects the same result
is obtained by a very curious provision.--_Some of their eyes are
short-sighted, and some long-sighted._ The simple eyes are supposed, by
Professor Müller, to be the short-sighted eyes, and the compound eyes
the long-sighted ones.

The number of _compound_ eyes in insects does not often exceed two,
these being made up, it will not be forgotten, by multitudes of single
eyes. But in a few, whose habits require that they should be endowed
with extraordinary means of vision, there are as many as four. If the
reader would betake him to the brook-side, and creep noiselessly along
its margin some summer afternoon, until he comes to a quiet glassy pool
where the water seems to have forgotten itself and fallen asleep, so
still, so silent, and so smooth does it lie, reflecting all the lustre
of the deep-blue sky overhead, he will surprise a dancing party of
insects busy waltzing at a wonderful rate, now skimming hither, now
shooting across the glassy pavement on which they sport, now joining
together and wheeling round and round, and again, as the king-fisher
comes fluttering down the river as though on some errand of immense
importance, breaking up their party and flying into a thousand holes
and corners to wait until all is quiet. Let him exercise his activity
and patience, and catch one of these giddy insects, which are known to
entomologists by the name of the _Gyrinus Natator_, and he will have
a good example of an insect provided with four compound eyes, so that
it can see not only before and behind, but upward into the sky, and
downward into the clear cool waters on whose surface its happy life is
spent. Some insects, like Cyclops of old, are furnished only with one
eye; and some, it is said, are quite blind--creatures that never feel
the blessed influences of the pleasant sunlight. Like the simple eyes,
the compound eyes are sometimes fixed on the end of a little footstalk,
so as to give the insect somewhat the appearance of being furnished
with a pair of opera glasses, or short telescopes.

In order to ascertain by what means the bee found its way to the hive,
whether by seeing it through its compound eyes, or otherwise, Réaumur
performed an interesting experiment similar in character to the one
before mentioned. He covered with a red varnish, which was quite
opaque, the compound eyes of a number of bees taken from the same hive.
He then shut them up in a box with several other bees from the same
hive which he left untouched. The box was only a few paces distant
from the hive from which the bees were taken. He then opened the lid
of the box, and those which had not been blinded instantly flew out of
it, and entered their habitation. Those whose eyes had been varnished
appeared not to care to leave the box at all, and seemed very unwilling
to make any attempt to fly; some of them, indeed, flew about from one
side to another, but did not go far. Réaumur then threw several of them
up into the air, and they immediately began to soar higher and higher,
until at length they went out of sight altogether! Réaumur compares
the poor insect's manoeuvres to those of a crow, whose head and eyes
mischievous boys have covered with a paper bonnet: the bird flies
upward until its strength is exhausted, when it drops again to the
earth. Not only did those bees which he threw up into the air thus soar
until they were lost to view, but all the most active of those which
were left in the box did so likewise, and Réaumur saw them no more. Not
one could find its way to the hive. From this experiment, and from the
preceding one, it is evident that both the compound and the simple eyes
are necessary to enable the insect to see perfectly; for when either
was varnished over, the bees could not find their way to their home
again. Réaumur imagines that the cause of the wheeling flight of bees,
sometimes observed, now in this direction, now in the opposite, may
arise from their eyes becoming perhaps in part obscured by the pollen,
or yellow powder of the flowers into which they plunge, the bee thereby
becoming partly blind-folded. These experiments are so interesting that
they deserve repeating, and it might be tried whether the result would
be different if only one eye were blinded. Other variations of the
experiments will also suggest themselves.

Although not organs of sufficient size to give their colouring the
requisite distinctness and amount of surface which would render it
very conspicuous in our estimation, the eyes of insects are often
exquisitely beautiful, and vie almost with precious stones in lustre.
Their most common colour is black, or brown; but the eyes of many
flies glow with fiery colours, some banded with green and purple, some
variously figured black and red. Some again glitter like burnished gold
shaded with the softest green; and some blaze with a play of colours,
like the diamond set in jet. The eye of the dragon-fly, in particular,
is a lustrous crystalline object of extreme beauty.

[Illustration: _Peacock Butterfly._]

We have dwelt as long as our limits will permit on this wonderful
apparatus of vision in insects: let us now turn our thoughts for a
little space to a pair of organs which are, perhaps, of all others the
most characteristic of the insect tribes: these are the _Antennæ_. We
need scarcely explain what these are, or point them out to the reader,
since they are so familiar to most persons, but under the erroneous,
or, at any rate, the questionable expression--"the feelers." We have
an excellent specimen of _antennæ_ in those of the butterflies, in
which insects they are very long and elegant organs. They are attached
to the head by means of a beautiful joint, called a ball and socket,
the same as is often adapted to garden watering engine-pipes, so as to
enable them to be moved about in all directions. They are never found
absent in the perfect insect, and are manifestly organs of considerable
importance in the insect economy. As to their structure,--when
examined under a microscope, antennæ are found to be composed of a
variable number of small round pieces, covered with a horny or leathery
skin, but within being softer and hollow, so as to form a series of
tubes placed end to end, all connected together in such a manner as
to admit of free movement between each joint, so that the insect can
bend them into any shape it may find expedient for its purposes. But
it must not be supposed that all antennæ are similar in form, or there
would be a risk of their being continually mistaken by the reader for
some other organ. The cut on the next page will, at a glance, exhibit
the astonishing variety of form assumed by these organs. The common
cockchafer is possessed of antennæ as strikingly different in form from
those of the butterfly, as if they were really distinct organs intended
and adapted to serve different purposes. Some are long and thread-like,
some resemble a necklace of pearls, some are notched like a saw, some
have a resemblance to a fan, some are like a club, some resemble a
fork, and some a feather; in short, their variety of form is almost
endless: and they differ as much in length and in thickness; for while
the antennæ of some insects are as long as, or even longer than, their
bodies, those of others are very short, and little prominent; and while
some are as thin and fine as the finest hair, others are nearly as
thick as the true body of the insect. Let us now ask what is the use of
these singular organs of the insect?

[Illustration: _Various Antennæ._]

From a hint which has before been dropped, it is probable that the
answer to this question will be readily anticipated. Various facts
appear to show that they may be the insect's _ears_! "Can it be that
such is their function?" some may exclaim, calling to mind that ears
in other creatures are so different in appearance and structure from
these organs. There have been many opinions on the subject, and some
have maintained views completely opposed to this idea. But the greater
number of entomologists seem to consider this as their most probable
function. If they are not ears, we are not able to point to any other
organs in the head which are. From a number of facts it is certain,
that insects can hear; from which it is equally certain, that they
must possess special organs. We may, therefore, until the contrary is
shown with respect to them, fairly be allowed to consider the antennæ
as these organs. The opinions of Messrs. Kirby and Spence on this point
are conveyed in the following words:--"They conceive that antennæ
by a peculiar structure may collect notices from the atmosphere,
receive touches or vibrations, and communicate them to the sensorium
(or brain), which, though not precisely to be called hearing, may
answer the same purpose." The late celebrated Dr. W. F. Erichson of
Berlin, by means of the microscope, has discovered in all insects, and
especially in those most remarkable for their powers of smelling, that
these organs are furnished with a number of fine pores, clothed with
membrane, which he regards as organs of smell.[U]

Every one has heard of M. Pelisson, the prisoner at the Bastile, and
his spider companions of the cell. This gentleman had, by patient
training, engaged the attention of a spider, which used every day to
come and listen to a solo on his violin, after which it would make its
retreat again to its home. Now it is clear, that this little insect not
only heard, but even enjoyed, the notes of his instrument; which would
have been impossible, had it possessed no ears. Then again, every one
must have noticed the start which a fly will make if some sharp noise
be made near it, and how actively it will move its legs, and seem to be
put all on the _qui vive_. A little every-day observation will furnish
us with many similar instances. "A little moth," writes one of the
last-mentioned authors, "was reposing on my window; I made a quiet,
not loud, but distinct noise; the antenna nearest to me immediately
moved towards me. I repeated the noise at least a dozen times, and
it was followed every time by the same motion of that organ; till at
length the insect, being alarmed, became more agitated and violent
in its motions. In this instance it could not be _touch_; since the
antenna was not applied to a surface, but directed towards the quarter
from which the sound came, as if to listen." Can we question that the
merry grasshopper, chirping all day in the field, is heard by its mate?
or that the cricket on the hearth sings for its fellows, or only to
please _our_ ears? or does the tap of the death-tick beetle, formerly
commemorated, draw forth no answering tap from its companion on the
other side of the post? All these instances, and countless more that
might be mentioned, indicate, beyond a question, that insects have the
faculty of hearing, and render it extremely probable that the antennæ
are the organs by which this function is performed.

But it is probable that they serve another and not less important
purpose. The country folk, who are generally very weather-wise, and
whose sayings always deserve a great deal of attention, because
they are very commonly founded both upon observation of facts, and
experience, will always assure us that the high flight of swallows in
their search after insects is a certain token of fair weather; their
low flight of approaching wet. Why is this? Can insects foretell the
state of the weather? and if so, by what means? That insects have a
meteorometrical power of foretelling the state of the weather, appears
beyond a doubt. To select a few instances. Bees, our exemplars in so
many points, might be consulted with advantage, and would often give
us better information as to whether an over-coat or an umbrella would
be probably required, than the not always trustworthy barometer. When
engaged in their daily labours, if a change of weather to rain is at
hand, although the sun may yet shine and the sky remain clear and calm,
they foresee it, and return suddenly to their hives. Hence in weather
of an unsettled description they never undertake journeys far from
home, but make short excursions to and from their hives, being never
absent long at a time; and if we find a bee wandering far from its
hive, it may be taken, on the other hand, as a pretty sure prognostic
that top-coat and umbrella may be left at home for _that_ day at
least. Ants, as we have already noticed, possess the same faculty of
weather-wisdom, never allowing their larvæ to be caught in a shower.
The abundance of insects in our houses in wet weather, is a familiar
observation; we are assured that in hot countries their excessive
numbers, during the rainy season, make these little creatures almost
as terrible as a plague to all who are within--climbing up the walls,
scrambling into the dishes, drowning themselves in the soup-tureens, or
putting out the lights with their bodies. In hot and sultry weather,
when a black cloud or two in the far horizon give token of a coming
storm, insects abound in the air; but as the heavens grow black, they
disappear; and before a drop of rain has actually fallen, we may look
in vain for them.

That the antennæ are the organs by which this knowledge of coming
events with regard to the weather is obtained by the insects, appears
probable. They may, perhaps, perceive by their delicate surfaces,
changes in the _electrical_ condition of the air, which are quite
insensible to ourselves: and as all change of weather is preceded and
accompanied by changes of electrical balance of one kind or another
in the air, they may be thus forewarned of the coming danger. The
following is the manoeuvre of a large number of insects of the beetle
tribe. When they are about to move from any station where they have
been at rest, the first thing they usually do before they move a step,
is to bring forward and expand their antennæ, which have previously
been folded up out of the way. They open them as widely as possible,
so as to expose them to all the influences of the air, and then, if
they be satisfied, they unfold their wings and take their flight. We
might compare this proceeding with that of one of ourselves looking
up at the direction of the wind, or tapping the weather-glass in the
hall, previous to setting out for the day! Too much stress, however,
it must be added, is not to be laid upon this point; for while it is
unquestionable that insects have knowledge of the weather, it is of
course very difficult to ascertain with certainty whether it is by
means of their antennæ, or by the general feeling of their bodies;
analogous, perhaps, to what rheumatic persons feel when the wind goes
round to the _north-east_.

There is a still more singular use of the antennæ, which deserves to
be mentioned. These organs appear to be the principal instruments
of _speech_, if we may use such a term, or, at any rate, of the
communication of intelligence. When the soldier ants go out upon their
expeditions, and have left the nest, previously to setting off, they
touch each other with their antennæ and forehead on the trunk; and this
is their signal for marching, for as soon as ever a soldier feels this
tap, he immediately puts himself in motion. When, also, they have any
discovery to communicate, they strike with them those that they meet,
in a particularly impressive manner; and if a hungry ant wants to be
fed, it touches with its two antennæ, moving them very rapidly, those
of the individual from which it expects its meal. They appear to salute
one another by gently tapping each other's antennæ, as we should shake
hands on meeting an old friend!

M. Huber has related an account of some interesting experiments of
his on a hive of bees, which strikingly proves that the antennæ are
really organs for the transmission of intelligence. He wished to
ascertain whether, when they had lost a queen, they discovered the
sad event by their smell, their touch, or any unknown cause; for such
a loss, in the course of a single hour, is made known in some way or
other to the whole hive. In order to ascertain this, he first divided
a hive by a grate which kept the two portions a few parts of an inch
separated from each other, so that the bees could not come at each
other, although any scent could easily have passed. In that part in
which there was no queen, the bees were soon in great agitation; and
as they did not discover where she was confined, in a short time they
began to construct royal cells, after which they grew more calm. Mr.
Huber next separated them by a partition through which they could pass
their antennæ, but not their heads. In this case, the bees all remained
tranquil, neither intermitting the care of the brood, nor abandoning
their other employments; nor did they begin any royal cell. The means
they adopted to assure themselves that their queen was safe, and to
communicate with her, was to pass their antennæ through the openings of
the grate, A most curious spectacle thus presented itself; an infinite
number of those organs might be seen at once, as it were inquiring in
all directions; and the queen was observed answering these anxious
inquiries of her dutiful subjects in the most marked manner; for she
was always fastened by her feet to the grate, crossing her antennæ with
those of the inquirers.

While we have been anxious to show that the function of feeling is not
the important and principal office of these singular organs, it would
be far from correct to state that the antennæ are not occasionally
employed, to use the popular term, as "feelers." All who have paid
any attention to the motions of insects must have seen the antennæ
actually employed as it were in exploring the number or nature of
objects immediately around. From these and the preceding remarks, it
becomes manifest, that, next to the organs of sight, the antennæ are
most important and useful appendages to the body of the insect. When
we consider the various purposes they serve, we become much perplexed
to understand how it is possible for one organ to fulfil such varied
duties; nor can it be explained. We are unable to conceive of the
senses of insects except by comparing them with our own; and in our
case there are no organs which can receive, and, at the same time,
communicate, intelligence. Our ears, eyes, nose, and the other organs
of the senses, have only one function severally assigned to them;
and had they more, there would probably be no little confusion in
our perceptions of external things. Such confusion does not probably
exist in the insect; but it is very possible that its perceptions are
somewhat different from ours.

Before we leave the region of the head, we have the important task
to fulfil, of describing the mouth of the insect: this part is more
complicated than the organs we have as yet seen, and requires,
therefore, a considerable degree of our careful attention to enable
us to do justice to it, and to carry in the mind a clear view of
this interesting portion of an insect's structure. "If," writes Mr.
Westwood, "a beetle, and a butterfly, a house-fly, or an aphis, be
examined whilst feeding, a totally different apparatus will be found in
each, although perfectly adapted for the mode of feeding. The beetle is
employed in gnawing and tearing in pieces hard or fleshy substances:
its instruments of manducation are, therefore, horny and robust. The
butterfly, on the contrary, has to seek its food at the bottom of the
tubes of flowers; and here in the glowing beams of the sun it revels
in its existence, and sips the most delicious nectar. It is necessary
for this purpose that it should be provided with a long and slender
instrument; but, from the very structure of this apparatus, it is
essential for its defence, that, so soon as the insect has ceased
feeding, the instrument should be lodged in a place of safety. It is,
therefore, rolled up in a beautiful spiral direction, and laid to
rest between a pair of hairy appendages, which will defend it from
injury. If we observe a common fly sipping up a drop of spilt wine, or
revelling upon a morsel of sugar, it will be found that its mouth is
totally unlike either of the former: it is short, thick, and fleshy,
and acts as a sucker, the nutriment ascending through the canal which
runs upward into the throat. The aphides and all their brethren have a
mouth differently constructed, being a long and slender pointed canal,
of a fleshy, or leathery substance, but furnished internally with
several slender bristles, which the insect employs as lancets to wound
its prey. In the flea, again, the structure is quite different."

[Illustration: _Proboscis of the Honey-Bee._]

[Illustration: _Proboscis of Carpenter-Bee_]

To the variations in the mouth of each of these insects it has been
thought good to attach a distinct name. When, for example, we speak of
a bee's _proboscis_,[V] we speak actually of its mouth. The mouth of
the butterfly is called by most entomologists _antlia_; that of the
aphis a _promuscis_; that of the flea a _rostrulum_. But the reader
must not allow himself to be confused by these terms; they all are but
names for modifications of the same part--the mouth. When the butterfly
plunges its long tube into the flower--when the fly intoxicates itself
with a drop of syrup, using its _proboscis_ to pump it up--and when the
flea thrusts its _rostrulum_ into our flesh, and quaffs our life-blood
as though it were nectar,--let us not forget the mouth is the organ
employed in each of these cases, varied and altered in form though it
certainly be.

[Illustration: Diagram of the mouth.--_a._ The _Labrum_, or upper lip;
_b._ The _Mandibles_, or upper jaws _c._ The _Maxillæ_, or lower jaws;
_d._ The _Labium_, or lower lip.]

In all cases, the various parts of the mouth may be reduced to six,
the names of which deserve remembering, and this will be rendered
easier by the accompanying diagram, in which they are all separated and
lettered, so as to distinguish each part; these six parts consist of
four side-pieces, and two other organs, one above, the other below. The
name of the upper organ is the _upper lip_, or in Latin, _labrum_; that
of the opposite lower one, is the _lower lip_, or _labium_. The upper
pair, of side-pieces, are called the _mandibles_, or upper jaws; the
pair below are the lower jaws, or _maxillæ_.

Let us now briefly mention the use of these various parts of the
insect's mouth; beginning with the upper lip, (_a_) or _labrum_. Unlike
that organ in ourselves, the insect's upper lip is generally, in such
insects as bite their food, a plate of horny substance, which serves
the purpose of an upper covering to the rest of the mouth. Like our own
upper lips, however, that is to say, like those of men, at least, it is
fringed with a sort of _moustache_ in most cases.

The _mandibles_, (_b_) or upper jaws, in the biting insects, are
instruments for cutting the food in pieces. When we bite our food,
the movement of our jaw is upwards and downwards; but in the insect
it is like that of a pair of scissors, or from side to side! These
jaws are sometimes frightful-looking instruments, resembling, in the
stag-beetle, _horns_; and their power is proportionally great. Although
their general use is to masticate or crush the food for the insect,
this apparatus is often employed as a formidable weapon of defence, or
offence; and very frequently in the excavation of a nest or retreat for
the insect. They are sometimes so constructed, as to look as if they
were furnished with several teeth.

[Illustration: _The Stag-Beetle, representing its enlarged Mandibles,
like horns._]

The _maxillæ_, or _lower jaws_, are less firm and strong than the
preceding; but they are more complicated in their structure, and have
attached to their sides remarkably delicate little processes like the
antennæ, which are called the _palpi_, or, less properly, _feelers_.
The lower jaws are much varied in structure in different insects; as
may well be imagined, when it is mentioned that the long and beautiful
spiral tube of the butterfly, by which it drains the juices of the
flower, is, in reality, composed of the maxillæ, or lower jaws. In
ordinary cases, the principal use of the lower jaws appears to be to
hold the food, while the upper jaws bruise and crush it; but their use,
of course, varies with their structure and modifications.

The last part of the mouth is the _labium_, or lower lip. This also is
a very complicated organ, generally serving to close the mouth from
beneath, like the upper from above. It boasts, like the same organ
in higher animals, of a _chin_ below it, called the _mentum_, and on
each side of it are a pair of feelers, or _palpi_, like those of the
maxillæ. In the centre a little tongue-like projection is visible in
the figure, which is sometimes called the _tongue_, but perhaps not
correctly, if by that term is meant the apparatus for _tasting_. The
lower lip is as much varied as the maxillæ.

It would be impossible, without going too far into minute technical
details, to explain to the reader how all these various parts of the
mouth are so modified, and altered, as to assume the very different
appearances presented to us in the insects already mentioned. This
pleasure must be reserved for the time when, well acquainted with the
generalities of insect history, which alone form the scope and subject
of this little work, he feels anxious to study entomology as a science;
and he will find a number of excellent books which will then well repay
his attentive perusal, and satisfactorily answer all his inquiries on
this and other difficult topics connected with this science.

It cannot fail to be noticed, that in this description of the insect's
mouth no mention has been made of its organs of _taste_. Its eye, and
probably ears, and means of touch, have all come before us; but where,
it will be asked, is its tongue? The little organ mentioned as a part
of the insect's lower lip, although strikingly resembling a tongue in
some instances, is in others very different from it, and appears in
such cases to be quite unfitted to act as the organ of taste. We must,
therefore, suppose, that other parts of the lower lip or mouth have the
same faculty in addition to the so-called tongue. It is very certain
that insects have the faculty of tasting, and also of discriminating
between their food; as few will be disposed to question, who will
place a plate of salt, and a plate filled with moist sugar, in a
sunny window on a fine day; it will soon become evident which will be
favoured with the attention of the flies.

Neither has any mention been made of a _nose_.[W] A common flesh-fly,
however, will soon satisfy us, that it is not devoid of some organ or
other which answers this purpose. If we cover a piece of meat under
a cloth, or put it into a wire safe where it is certain that the fly
cannot see it, it will scent it out as readily, or even more so, than a
cat or a dog would. Sometimes this insect's nose proves a treacherous
guide, for a plant has been described, called the _carrion-flower_,
which diffuses an odour like that of putrid meat, which attracts the
fly, and induces it to deposit its eggs thereon, under the idea that
its future young will thus be hatched upon a certain source of food;
but in vain, for they perish almost as soon as born, finding nothing
in the plant whereon to exist.[X] But as to the precise seat of the
organ of this sense, opinions are greatly at variance. Some believe it
to exist in the _spiracles_, some in the mouth, and some in a special
organ which they call the nose, but which does not seem in reality to
fulfil that office, at any rate, in the generality of cases. M. Huber
showed the existence of this faculty to lie somewhere about the mouth,
by some interesting experiments upon bees. He presented successively
to all parts of a bee's body a camel-hair pencil dipped in oil of
turpentine, to which most insects are extremely averse, but the bee
took no notice of it. He then took a very fine hair pencil, while
the bee had extended its proboscis, and presented it to its eyes and
antennæ without effect; but when he pointed it near the cavity of the
mouth, above the insertion of the proboscis, the creature started back
in an instant, quitted its food, clapped its wings, and walked about
in great agitation, and would have taken flight if the pencil had not
been removed. On this it began to eat again; but on the experiment
being repeated, it showed signs of similar discomposure; oil of
marjoram produced the same effect, and more promptly and entirely. He
then seized several bees, forced them to unfold their proboscises,
and stopped their mouths with paste. When this was sufficiently dry to
prevent their getting rid of it, he restored them to their liberty;
they appeared by no means incommoded at being thus gagged, but moved
about and breathed as readily as their companions. Huber then tempted
them with honey, and presented to them, near the mouth, oil of
turpentine and other odours that they usually have an aversion to; but
all produced no sensible effect upon them, and they even walked upon
pencils saturated with them!

Leaving now the head of the insect, it is necessary for us to make
some mention of the parts attached to the _thorax_, or trunk. In the
head division we have seen that the various organs of the senses are
situated: we shall now find that in the thorax division are placed the
organs by which the insect is either wafted in rapid evolutions to the
highest air, or runs with incredible rapidity along the surface of
the earth. We have already described, on a previous page, the general
structure of an insect's wing. It remains, therefore, for us here to
advert to a few other facts in connexion with these elegant appendages.

[Illustration: _The House Fly. Natural size and magnified._]

[Illustration: _Scales of Insects Wings magnified._]

The natural number of wings in the insect world is four, arranged in
two pairs. But this number is obscured by the modifications to which
in many instances one or other of the pairs becomes subject; and we
should, if this were not remembered, become somewhat confused at taking
up the first insect that came in our way, which would probably be the
common fly, and finding that we could only recognise two large wings
instead of four. In this tribe of insects the hinder pair of wings
is reduced to a pair of slender knobbed filaments. Some insects are
without wings at all. The ant, the bee, the dragon-fly, the house-fly,
and many other insects, are furnished with wings of gauze-like
transparency and structure, often crossed in a curious manner by the
_nervures_, of which we before had occasion to speak. These wings are
called _membranaceous_. In the moth and butterfly tribes the wings
are covered with what appears to be a delicate, beautiful powder, but
is in reality a multitude of exquisite scales, of the singular forms
represented. The engraving shows the shape of the scales on the wings
of these insects; on examination with a good lens, it appears that the
long and hair-like scales are planted at the margin of the wings, and
contribute to give to the edges that beautiful feathery look which is
so much admired, while the short scales were placed principally on
the middle portion of the wings; their numbers are almost infinite.
If a butterfly is allowed to flutter awhile in a box it will cover
every portion of its surface with them, and yet, on being permitted to
fly out, we may scarcely perceive that it has lost any of its fairy
plumes. Whether Leuwenhoek actually took the trouble to count so many,
or arrived at the result from calculation after counting those on a
given space, we do not know, but he declares that he found more than
four hundred thousand on the wings of the silk-worm moth; and in those
of larger moths and butterflies the number must greatly exceed this.
They are generally arranged like the tiles on a house-roof; and if
they are scraped off, the minute dots where each was attached becomes
distinctly visible. The term used to indicate the tribe of insects
to which the moth and butterfly appertain, is, as has been before
remarked, _Lepidoptera_, or "scale-winged," from this very fact. Some
membranaceous wings are clothed with fine hairs.

[Illustration: _Blight-Beetle. Natural size and magnified._]

If we take up a beetle, and look for its wings, for the first time,
we shall probably fail in detecting them, that is, of course, if the
insect has not been observed in the act of flying. On examining the
body we see, indeed, a pair of shining horny plates on its back; but
surely these are not wings? Presently, the insect having mounted to
the top of our finger, prepares for flight; its two hard cases fly up,
and, behold! from beneath them appears a pair of the most beautiful
gauze-like wings, which it quickly unfolds, puts into motion, and
then flies away. The two thick and horny covers for these delicate
organs are called _elytra_, or "wing-cases." They are really the
first pair of wings, much thickened; and their use is to protect the
delicate membranous wings of the hinder pair, beneath them. When the
insect flies, they open like a box-lid, and are carried out of the way
of the other wings; when the insect rests it carefully folds up its
other wings, and then these close over them, and preserve them from
all injury. As the insects in which they are found frequent places of
danger, burrow underground, or take up their abode under stones, it is
manifest how admirable a contrivance this is for such purposes, and
how efficiently the fragile wings will be covered and protected by
such shields. The first pair of wings is sometimes thickened to the
consistence of parchment as a cover to the other wings; and they are
then called _tegmina_, or "wing-covers."

There are two other circumstances in connexion with this part of our
subject, which deserve noticing. If the reader will take into his
hand a large blow-fly, and carefully examine its body with a lens
near the spot where the wings are connected to it, he will succeed in
discovering two organs of a curious kind. One of these, is a small
membranous piece connected with the trunk-end of the wings, and is
generally called the _winglet_, or _alula_. The other looks like
a little drumstick hanging down, and is called the _balancer_, or
_poiser_, or in Latin, the _halter_, or bridle. It is not clear of
what use either of these organs is. Since the winglets are the largest
in the heaviest bodies, and are altogether wanting in the lightest,
it appears probable that one of their principal uses is to assist the
wings during flight. If one might hazard the conjecture, perhaps they
act like the _parachute_ of a balloon. As to the so-called _balancers_,
it has been considered that they serve to poise the insect while
flying. Dr. Derham considered that they kept the body steady during
flight; and he states that if either a poiser or a winglet is cut off,
it will fly awkwardly and unsteadily, as if it had lost some very
necessary part. Another observer states, that he cut off the winglets
of a fly, leaving both its wings and poisers; but it could no longer
fly. He also cut off, in another fly, the poisers alone, and the same
result took place. On cutting off both the poisers of a crane-fly, he
says it was unable either to fly or walk.[Y] Mr. Westwood says he has
seen the poisers beat rapidly upon the winglets like drumsticks on a
drum, and it has been supposed that this action is the cause of the
_hum_ made by the insect in flying. This is doubtful, because it has
been found that after the winglets are cut away the humming sound is
still produced; and some humming insects have no winglets.

[Illustration]

So much importance did Linnæus, the great father of natural history,
attach to the character of the wings in insects, that he arranged
the various families of insects under several heads expressive of
the leading character of their wings. The orders into which he thus
divided insects are seven in number: 1. _Coleoptera_, or case-winged;
2. _Hemiptera_, or half-winged; 3. _Lepidoptera_, or scale-winged; 4.
_Neuroptera_, or nerve-winged; 5. _Hymenoptera_, or membrane-winged; 6.
_Diptera_, two-winged; and, 7. _Aptera_, or wingless: the Greek word
_pteron_, signifying "a wing," furnishes the termination to each of
these titles; the prefix is also derived from the Greek, and its import
may be derived from the translation attached to each. This system has
been extended by modern entomologists, who have subdivided the 2d, 5th,
and 7th orders into additional ones.

In the opposite cut the insects represented illustrate each of the
Linnæan orders. They are--1. a Beetle; 2. an Aphis; 3. a Butterfly; 4.
a Bee; 5. a Dragon-fly; 6. a House-fly; and, 7. a Spider.

As these organs exhibit to us in the most conspicuous manner the
exquisite beauties wherewith it has pleased God, the Almighty Creator,
to adorn the insect world, we may be allowed to make some reference
to the colours of the wings, before proceeding to speak of those
organs by which the insect moves on earth. Some, of the beetle tribe,
are like tiny masses of burnished metal gleaming with colours of the
most exquisite description. A vast number of locusts are remarkable
for the splendour of their wings. Many dragon-flies are adorned with
wings vying with those of the butterfly in loveliness. The wings of
many flies are exquisitely painted with the most brilliant metallic
hues, green and gold; and even those of a house-fly are often very
beautiful by their having the property of _iridescence_, or reflecting
the prismatic colours of light. But insects of every tribe, however
splendid in attire, fade before the glories of the butterfly tribe.
Linnæus, speaking of the splendid colours of these insects, and
particularly of the gorgeous tints which appear on the upper surface
of the wings of a butterfly called the Morpho Menelaus, and another,
justly observes, that there is scarcely anything in nature that for
brightness and splendour can be paralleled with this colour. It is
a kind of rich ultramarine, that vies with the deepest and purest
azure of the sky; and what must cause a striking contrast in flight,
the prone surface of the wings is as dull and dark as the opposite
is brilliant; so that one can conceive this insect to appear like a
planet in full radiance, and under eclipse, as its wings open and
shut in the blaze of a tropical sun. The scales on the wings of some
species shine with such extraordinary intenseness and brilliancy,
that it is impossible to look at them in a bright light, as they
completely dazzle the beholder. Messrs. Kirby and Spence say, they
"know no insect upon which the sight rests with such untired pleasure
as upon the lovely butterfly that bears the name of the unhappy Trojan
king (_Papilio Priamus_); the contrast of the rich green and black
of the velvet of its wings with each other, and with the black of its
abdomen, is, beyond expression, regal and magnificent." What adds to
the beauty of the wings of this tribe of insects is the appearance
of the beautiful spots like eyes, which are so familiar to us, and
which are almost without a parallel, except in the animal world. This
ornament gives to the wings of a butterfly an indescribable life and
beauty, and constrains us as we contemplate it to acknowledge that
'Solomon, in all his glory, was not arrayed like one of these.' The
astonishing variety of combination in the colours communicates an
inexpressible charm to these insect glories: here is a lustrous blue,
a glowing orange, a delicate lemon, an exquisite pink, a fiery copper,
or a spotless white. None but a Divine hand could have produced such
effects as are exhibited in these most gorgeously painted organs. No
work of man will endure comparison with them. The most elaborately
finished miniature upon which the artist may, in the features and
dress of the person, have expended all the resources of his art in the
production of harmonious and pleasing tones of colour, appears but as
a muddy, lustreless patch, when placed side by side with one of the
butterfly-beauties of the tropics, or even of our own green fields.

[Illustration: _Hind Leg of a Bee._]

We must not, however, allow the fascination of these beautiful objects
to engross our whole attention; and it is now time for us to state some
particulars connected with the _legs_ of the imago, or perfect insect.
Six is the true number of legs which belong to the insect in the imago
state. They are connected to its body at the thorax, and are formed of
a series of minute tubes, provided internally with muscles and nerves.
They are commonly divided into four parts; _a_ the haunch, _b_ the
thigh, _c_ the _tibia_, and _d e_ the foot.

The front pair of legs, or, as they are generally called, the
_forelegs_, are considered by some authors to be really the insect's
_arms_, the last portion of them being the _hand_. Certainly they are
often as useful to the insect as is this admirable organ to ourselves;
not only are they serviceable in walking, but they also enable the
insect to climb, to lay hold of various objects, or to catch their
prey, to dig in the earth, and in many instances to clean the head
and face of the creature; an operation in which many of them, and
particularly flies and bees among our domestic insects, are most
praiseworthily particular; having apparently an aversion to nothing so
much as to a _dirty face and unbrushed jacket_! The other pairs of legs
are altered in various manners in order to fit them for the different
purposes for which they are required by the insect.

[Illustration]

The purposes for which the legs are put into requisition are, as will
be easily guessed, for walking or running, for jumping, for climbing,
and for swimming. Most surprising in all these respects is the degree
of agility and swiftness with which it has pleased the Divine Creator
to endow these insect-organs. M. Delisle once observed a fly, only
as large as a grain of sand, which ran three inches in half a second,
and in that space made the enormous number of _five hundred and forty
steps_. If a man were to be able to walk as fast in proportion to
his size, supposing his step to measure two feet, he would, in the
course of a minute, have run upwards of _twenty miles_, a task far
surpassing our express railroad engines, or the famous Seven League
Boots recorded in the nursery fable. In leaping, also, insects far
excel man, or any other animal whatever. The flea can leap two hundred
times its own length; so also can the locust. If a man were six feet
long, and could leap as high and as far as one of these insects, he
might stand near Bow Church in Cheapside, leap up into the air over
the top of St. Paul's cross and alight at the bottom of Ludgate Hill;
which would be something more wonderful than it has ever entered into
the minds of the writers of fairy tales to conceive of. The insect
called the frog-hopper can leap more than two hundred and fifty times
its own length. Some spiders can leap a couple of feet upon their prey.
The legs of insects that swim are generally peculiarly fitted for it,
either by their being expanded somewhat like an oar, or by having a
dense fringe of hairs upon them. The water-beetles, after rising to the
surface of the stream for a supply of fresh air, dive down to their
watery home again, taking a clear silvery bubble along with them; and,
in this action, they move with considerable rapidity their swimming
legs, which are clothed with hairs. The water boatman swims _upon his
back_ by means of his singularly formed legs. The little whirl-gig,
of which we have before spoken, swims by means of its legs, which are
paddle-shaped. By means, it may be, of some peculiar secretion, which
repels the water, some insects can actually walk upon its surface, and
that as readily or more so than upon land. Those who know the pleasures
of shooting with polished skates over clear ice, when it almost seems
as if we were moving in the air, and no more condemned to earth, can
imagine something of the delight these insects must experience, who
can glide as swift as thought over the glassy surface of the brook.
Sometimes the shape of the hind-legs is remarkably altered, and,
perhaps, the most extraordinary instance of this in the whole insect
world is, the foreign insect, which has been called the _Kangaroo_
beetle. The cut represents faithfully this most wonderful creature; and
we could almost fancy, as we looked at it, that by some accident the
front pair of legs and the head had been twisted round, leaving the
hind legs and part of the body turned in the opposite direction. It
need scarcely be added, that the origin of this insect's curious title
was derived from the resemblance borne by its hind legs to those of the
animal whose name it bears. In some insects the legs fold upon each
other, and are packed into a very small compass: this is particularly
the case in a species of wood-louse, which roll themselves up into
balls precisely resembling beads or pills, as may be imagined from
the following anecdote. A servant maid of the great Swammerdam, while
walking in the garden one day, found a large number of round, black,
shining beads, which were streaked with white bands, and presented a
very pretty and attractive appearance. Gathering a number of these in
her hand, she thought she would convert them into a necklace, or, for
ought we know, into a rosary, when, to her great surprise, the beads
became animated as soon as ever they felt the point of the needle, with
which she was about to thread them, and began to struggle actively to
get away; not, however, too quickly for her; for with a violent scream,
imagining the beads were bewitched, she ran into the house. Some of the
beetle tribe thus fold up their legs, and roll themselves up so as to
resemble little globular pebbles.

[Illustration: _Kangaroo Beetle._]

_The Abdomen_ is, then, the only remaining portion of the insect which
we have now to notice. It has no legs attached to it, and contains the
intestines, and other portions of the insect's internal anatomy. It is
formed of a varying number of rings, which are easily distinguishable
in the wasp and many other insects, and these rings are connected
together by delicate folds of membrane, fitting sometimes into each
other like the tubes of a telescope; in other instances fastened
together, like so many hoops, by their edges. In consequence of this
mode of structure it is often very movable, and may even be bent into
a half curve, in various directions, at the pleasure of the insect.
The common earwig is particularly gifted with this movableness of its
abdomen; and so are many insects which carry weapons of offence or
defence in their tails. These organs, or appendages, are deserving of
a brief notice, although it is probable that the structure of some of
them is already familiar to most readers.

[Illustration: _A Bee's Sting magnified._ _a_, represents the pair of
darts; _d_, a single dart; _b_, the poison-bag; and _c_, the sheath.]

The sting of the bee is, perhaps, as formidable a weapon as any of
those attached to the abdomen in insects; under the microscope the
structure of this apparatus appears in all its beauty. It is found to
consist of a sort of sheath, or scabbard, which is composed of two
pieces, and is of extreme fineness, as will be readily made visible
by placing a fine sewing needle by its side, when the latter will
more resemble a bar of iron from the smith's forge, or a kitchen
poker, than anything else; while the former will, under the strongest
magnifying power, exhibit a smoothness, elegance, and polish, of the
most beautiful description. When the bee thrusts forth its sting, it is
the sheath which we generally see, and not the more delicate apparatus
which is enclosed within it. Inside this scabbard is a pair of most
fine darts, which are even more delicate than the human hair, and
are therefore invisible to the eye, unassisted by a good lens. These
darts are notched like very fine saws at the end, the teeth being so
directed as to oppose the retraction of the instrument if it is thrust
into the human skin; the sting being therefore left in the wound, and
the wounded person having the comfort of knowing--if we should call it
a comfort--that the insect will surely die speedily, in consequence
of its attack upon him. An exquisite adaptation of fine muscles is
attached to this weapon, by which it is forcibly driven home. The
venom which produces the pain and inflammation is contained in a small
muscular bag in connexion with the sting; and when the latter is thrust
out, the poison is also forced out and flows into the wound. The sting
of the scorpion is a less complicated, but more dangerous weapon,
though not often fatal. The earwig, though unprovided with a sting,
carries a most awful-looking forceps in its tail, which it can put in
action with great force on occasion of danger; and since it can twist
its abdomen about with great facility, it is a contrivance of which a
tender finger may well be afraid.

Among the wingless insects of Linnæus, is one which he has called
by a name which signifies that it has _got a leg in its tail_; and
this is actually the fact, in so far as that these insects have an
organ in their tail, which answers all the purpose of a leg. Some of
these little creatures, which are black, may be often found in spring
strewed in infinite numbers upon the surface of the water in ditches
or pools; and may be seen jumping about on the surface of the water as
if bewitched. At their tail is a fork-like organ, which is generally
bent under the body; but when they spring up they do so by quickly
unbending this fork, the resistance it meets with being sufficient to
carry it to a certain distance. Another insect is provided with eight
pair of springs in its abdomen; by means of which it can leap to a
great distance with most astonishing agility. Here we shall conclude
the external anatomy of the insect, in the imago state.




CHAPTER III.

RESPIRATION OF THE IMAGO.


Perfect insects breathe. That this is so, the following experiments[Z]
will satisfactorily prove. A spider and a fly were put into a glass
jar, the mouth of which was closed all but a hole by which a tube was
admitted. The tube was then connected with a pipe by which a supply of
common coal-gas was poured into the jar, and when it was considered
to be full of gas, and that all the air had been displaced, the tube
was closed, and the insects were left shut up in an atmosphere of gas.
In a few seconds both became very uneasy, the fly more particularly
so; and in a few seconds more the fly began to agitate itself, to
buzz against the sides of the glass, and to tumble over in the most
extraordinary manner; the spider ran hurriedly about, as if astonished,
and not knowing what to make of his new position; but presently he
became very quiet, and, turning on his back, looked as if dead. For a
minute or two the fly, which was a large, active, flesh-fly, continued
its noisy evolutions, dashing itself, as if intoxicated, on every side
of its transparent prison. At length, as if exhausted, it lay on its
back, its limbs paralyzed, but the wings still moving with extreme
rapidity, and causing it to spin round in the most singular manner.
Ultimately it, too, became perfectly without motion. After the lapse
of about ten minutes, fresh air was gradually let into the jar, and it
became most amusing to watch the return of both these insects, which
had previously been as it were in the very jaws of death, back to life
again; twitchings of their limbs, and slight convulsive movements,
were the first indications of returning activity; and in a few minutes
more both insects, now placed in a perfectly pure atmosphere, were as
lively as before the experiment, and were allowed to make their escape
into the open air. With other insects the same effects were produced
by saturating a piece of blotting paper with ether, and dropping it
into the jar, which was immediately covered over. In several other
experiments the newly-discovered powerful fluid _chloroform_, by means
of which the operations of surgery are performed without pain, was
employed; and it was remarkable to notice how quickly the insects were
overpowered with the vapour of this potent liquid. In no instance was
death produced by the gases or vapours employed. Wishing to destroy
without pain a beautiful specimen of a goat-moth, it was first
stupified with the gas, then transfixed with a pin, and again plunged
in an atmosphere of gas all night long; but alas! for the unhappy
insect, the morning dawned, and it was yet alive.

In these simple experiments, which were repeated sufficiently often
to render the results certain, we have a most interesting proof that
insects breathe. The first struggles and apparent intoxication can
be compared to nothing more exactly than to the same phenomena when
they take place in human beings breathing the vapours of ether, or
chloroform. The subsequent state of insensibility was precisely
similar to that induced in persons who are put under the influence
of these vapours. An amusing instance of the restorative powers of
fresh air occurred in the course of these experiments. A blue-bottle,
which was purposely selected of as large a species as could be found,
was first intoxicated and rendered insensible by coal gas, and was
then as quickly as possible put into a net of the geometric spider:
instantly the spider flew upon his bulky captive, but the fresh air
began to take effect on the fly, and it commenced struggling in the
most furious manner. Although the spider cast out a cloud of web, and
in the most energetic manner endeavoured to envelope its prey, the fly
seemed likely to be the victor; one of its large and powerful wings got
free and flapped violently until the meshes of the web gave way, or
was, perhaps, broken by the weight of the insect, and fly and spider,
being suspended in the air, spun round so swiftly as to be quite
indistinguishable. Ultimately, the spider conquered; and, suspending
the huge body of its victim by a rope in the air, returned for a short
time to its den.

If insects do not breathe, then all these results are quite
unintelligible; for it would be immaterial to the insect what
atmosphere it might happen to be placed in. A number of illustrious
authors have recorded the result of their experiments upon the effects
of other gases on insects. Bees, and other insects, have been placed
under the exhausted receiver of an air-pump, and death ensued in a
short space of time. It has also been found, that when the bodies
of insects are covered with oil or grease, so as to stop up their
breathing pores, they soon expire. It has been proved by carefully
conducted experiments performed by Mr. Ellis, M. Sorg, and other
observers, that on placing flies in a measured quantity of atmospheric
air, at the end of a day or two almost the whole amount of the oxygen
of the air had disappeared, and the same amount of carbonic acid
had appeared in the chamber in which the insects were confined. We
need not, however, after all that has been said on the subject of
the respiration of insects in their various stages, enter into any
further proofs that insects breathe not less perfectly in their imago
condition than in any of the preceding states; in fact, they perform
this function far more prominently in this their last state than in
any of the foregoing. It will also be unnecessary to enter into a
consideration of the minute particulars connected with this subject, as
several of these have been previously glanced at.[AA]

The air enters the body of the insect at the spiracles, or
breathing-pores, which are arranged along the abdomen, and situated
at the side of the wings, and is received by a large tube on each side
of the body, running its whole length, or nearly so, as we before
mentioned. This tube, and those which it gives off as branches, are
called _tracheæ_, or air-pipes. The tracheæ are formed in the most
wonderful manner, so as to keep them always open, that the air can
readily pass through them. Perhaps some of our readers have seen the
contrivance adopted by sailors in order to blow air down into the hold
and cabins of the ship; for those who have not, we may take the liberty
of mentioning, that it is a large tube made of canvass, open at the
side near the top, so as to catch the wind, while the bottom of it
opens into the cabin. Now, the sailors always place the mouth of this
tube towards the wind, which is forced down the tube into the cabin
either by its own speed, or by that of the vessel, in the case of a
steamer, and so fills the cabin below continually with fresh air. But,
it will be asked, how do they contrive so to keep the sides of the bag
from flapping together as to prevent them from closing? By imitating
a contrivance which exists in the trachea or air-tube of the insect;
they place at certain distances inside this canvass tube a series of
wooden hoops, which entirely prevent its collapsing, as it otherwise
would do. The most minute air-tubes of an insect are furnished, not,
indeed, with a series of rings, but with what serves the same purpose,
a firm but delicate coil of cartilage like a spiral spring, over which
the membranous lining of the tube is stretched. Thus these tubes remain
constantly open; and, whatever may be the movements of the insect, they
retain this position. The tracheæ branch out in a most wonderful manner
inside the insect's body: as thickly as in our bodies and in those
of animals the fine blood-vessels divide until they form a mesh so
close that we cannot prick ourselves with a pin without piercing some
little tubes, and drawing blood; so in those of the insect, the minute
air-pipes run in every direction, and divide into countless thousands
of branches, which only become visible under the highest powers of a
good microscope. The large tubes are seen without difficulty in many
insects; and a drawing, which may give some idea of the immense mass of
air-tubes existing in the body of an insect, is annexed: all the rest
of the body is supposed to be cut away, and the larger tubes only are
shown, as it is impossible to represent the smaller ones so as to give
a clear view of their arrangement; they would cover the drawing like a
cloud of the finest and most delicate lace-work. In short, in insects,
there being no separate lungs in a particular place, as in the animal
frame, the air is necessarily carried all over the body, so as to be
supplied even to the most minute parts; thus the lungs may be said to
extend through the whole body.

[Illustration: _The Air-tubes magnified._]

[Illustration: _The circulation in an Ephemera. The arrows represent
the direction of the blood-current._]

As the reader has laid his finger on his pulse, or felt his heart
beating within him, or seen a drop of blood ooze from his wounded hand,
have the questions never occurred to him,--Have insects blood-vessels,
and a beating heart? And if so, have they blood like ours? Many a
wise man of old, even the great Baron Cuvier himself, has supposed
that there was no circulation of the blood in insects. But, with
a magnifying glass and a caterpillar before us, we shall soon be
satisfied that this is a great mistake, for by carefully looking
along the insect's back we shall perceive in that part a very evident
pulsation, as though a fluid were pushed at regular intervals towards
the head. The cut represents the circulation in the vessels of the
larva of an Ephemera. But insects have no heart, like that of man
and animals. What, then, can this beating organ be which we behold?
Although it is not like our heart, it is nevertheless an organ which
serves all the purpose of ours, and pumps on the blood with great
regularity. Instead of being a muscular organ of small size, but great
thickness, like our heart, it is in reality a long tube, called the
_dorsal-vessel_, running along the abdomen and thorax of the insect,
into which the blood is poured by the veins, and out of which it is
forced on towards the head by the regular contractions of its side.
This causes the beating movement which we saw in the caterpillar.
Perhaps there may be some curiosity to know whether an _insect's pulse_
beats faster or slower than ours. John Hunter counted thirty-four beats
in a minute in a silk-worm. Another observer counted thirty a minute
in a caterpillar of the pine-moth. But in the imago state the pulse
appears to move much quicker: and it is easy to make an insect's beat
extremely fast, by exciting or provoking it. Mr. Newport having done
so to a bee, counted as many as 142 beats a minute. In a middle-aged
man the pulse beats about seventy times in a minute; in a child seven
years old about eighty-five times; and at the age of fourteen about
eighty times. Hence it follows that our pulse beats about twice as
fast as that of an insect in the larva state: in the imago state it is
probably, as a general rule, at least in winged, active insects, higher
than ours.




CHAPTER IV.

FOOD AND DEATH OF THE IMAGO.


But we have something to say about the food of insects. Although it
has been already laid down as a general rule, that insects in their
perfect state, do not eat in any degree with the voracity they exhibit
in the larva form, it is nevertheless true that they do both require
and devour food in considerable quantities, and of various kinds. Some,
for example, are exclusively _vegetable_ feeders. They attack all the
parts of plants, not excepting even the root and the bark. Some, with
an elegant taste, select the yellow pollen of flowers for their dainty
and delicate food. And others, more refined still in their appetites,
will have nothing but the fresh distilled honey that lies hid at the
bottom of the flowers, pumping it up by the beautiful spirally-coiled
tube which forms a part of their mouth. Need we say these are the
butterflies? The fly loves a grain of sugar, or a savoury joint of
meat: and to other insects, to use a quotation of Mr. Spence's, which
prefer the paper of our Atlases, or maps,--

    ----"a river and a sea
    Are a dish of tea,
    And a kingdom bread and butter."

A large number also are _carnivorous_ creatures: need we mention the
spider-tribe? a name of terror to myriads of our summer insect-friends.
The beautiful _cicindelæ_, called by Linnæus the "tigers to insects,"
prey upon the whole insect race, and are endowed with powers of offence
and destruction, to a degree sufficient fully to justify this title. In
France, we are told, the butchers are very glad to have wasps attend
their stalls; since they drive away, and undoubtedly prey upon, the
numerous flies which frequent these places. The larger species of ants
are equally ferocious, attacking any small soft-bodied insect they may
meet with, and when killed dragging it to their nest. The beautiful
lady-birds, which we look upon with so much tenderness, remembering the
ditty,

    "Lady-bird, lady-bird, fly away home,
    Your house is on fire, your children will burn;"

are in the larva state furious destroyers of other insects, and will
gobble up aphides by the score in a very short time. The dragon-fly
too stands conspicuous among the insect devourers, not only in its
larva but in its perfect condition, and falls upon multitudes of
insects, plucking off their wings, and with savage relish devouring
their bodies. We are not, however, to suppose that the appetites of
carnivorous insects are confined to insect-food. The blow fly lives
upon and defiles by depositing its eggs in our butcher's meat. The
cockroach will polish a bone as clean as, or cleaner than, any dog
will, and, indeed, will consume almost anything that happens to come
in its way. Lastly, we may not omit to mention, that some insects have
to plunge their armed mouths into our flesh and that of other animals,
and to slake their raging thirst in a draught of our life-blood: among
which we will only enumerate the musquito, the gnat, and the flea. We
need scarcely say, that insects are provided with proper organs of
digestion.

Singular to add, some insects in the perfect state do not eat at
all. The silk-worm moth, and the _Ephemeræ_, are amongst this number;
they live so short a time, as not to require food. Some insects also
possess a most extraordinary power of abstaining from food. There
have been at different times wonderful tales related of human beings,
who, in a supposed trance, have endured the privation of food for an
extremely long time,--weeks, and even months. And more recently we
have an account of an Indian who suffered himself to be buried alive,
built over with bricks and mortar, and a great seal set upon the only
opening to his tomb, a guard being also set; and, after the expiration
of a certain time, before agreed upon, the sepulchre was opened, and
he was taken out--alive! All this is extremely wonderful, if we could
only feel certain that there was no deception in the case. But it is
nothing to what can be adduced from the insect world. The ant-lion has
been known to endure a fast of _six entire months_, and to be as lively
as possible at their termination. An author quoted by Messrs. Kirby and
Spence kept a spider in a sealed glass for _ten months_, at the end of
which time, though shrunk in size, it was as vigorous as ever. And Mr.
Baker relates that he once kept a beetle alive for three years without
food of any kind whatever!

When we call to memory the intense voracity of the insect while a
larva,--how insatiable its appetite, how extensive its ravages,--and
contrast it with the perfect insect, we are struck with astonishment.
Why is this, we ask, that in all cases insects eat less when they are
fully developed, than when in their infancy and youth? It is as if a
full-grown healthy man were to eat less than his little child a year or
two old. The reason appears to be, that in the imago state no further
changes (which consume a great deal of material, as may be imagined
when we remember the loss of substance in every cast of the skin) are
necessary; the insect only requires food sufficient to preserve its
life and activity in the state to which it has come, and needs no
laying up of stores of fat for future consumption. Fluttering awhile in
glorious apparel, through a world of flowers and sunshine, the period
of its life runs out, and its only further change is--to die, and
return to its kindred dust.

But, before this takes place, one last duty devolves upon the insect,
which, unfulfilled, would leave the world at its death with one link in
the chain of creation broken off,--this is, to make provision for the
continuance of its species. We have already said, that insects, as a
general rule, have been, no doubt in wisdom, destined to deposit their
eggs not knowing what is to come forth of them, and never enjoying that
happiness which is granted to many other beings,--the happiness of
parental love. Some most interesting exceptions to this rule will have
also been mentioned, in which a mother's love for her young has been
exemplified in a remarkable manner.

Yet, though denied this pleasure and privilege, the mother-insect
exercises, as we have before seen, all the care and forethought of the
most affectionate parent, in depositing its eggs, and in making such
arrangements as will be most conducive to the happiness and well-being
of its future progeny. We can scarcely say that in this it shows that
it possesses anything like such a feeling as that of a parent towards
its child. It takes the wonderful precautions, and performs the
singular actions, which have been already in part recorded in our first
chapter, in all probability without being aware of the reasons why it
should do so. How can it tell that its future progeny will eat this
food, or that food? How can the poor blow-fly, when it leaves its eggs
on our food, be certain that it is appointing a suitable place for the
birth-spot of its progeny? Why does it not select the green surface of
the leaf, or the warm corner of the window, or the bare earth, for this
purpose? We might say, perhaps, in this instance, that the insect is
only choosing the place where it obtains its own food. But what shall
we say when we find insects, such as the butterfly, depositing their
eggs upon plants which they never frequent at any other time, and from
which they never obtained a particle of food themselves? Some, for
instance, deposit them on the nettle, although never tasting anything
from this plant themselves, while the young which are to proceed forth
from the eggs feed voraciously upon it.

We cannot, in any way but one, account for this forethought. The
poor insect, left to itself, would undoubtedly deposit its eggs
indifferently anywhere; and the result would be, that its young family,
if hatched at all, would awake only to find themselves in a desert,
without food, or hope of reaching any, and would soon perish. Need we
say how it can be easily accounted for? Surely, only, because it is
God who has instructed these humble creatures, enduing them, if not
actually with the powers of foresight, at any rate with the instinct
which impels them to proceed in such a manner as if they were thus
endowed. By a most wonderful exercise of wisdom He has taught them to
distinguish even between the different species of plants; and rarely,
indeed, do we find that the insect commits a mistake, or selects a
wrong or fatal birthplace for its young.

Insect history is full of such instances of the great Creators wisdom
and love. Although they are not rendered conspicuous to every eye, they
are not the less real, nor the less amazing. In our Life of an Insect,
many have been the occasions when we have stopped to wonder afresh at
continually new and more striking indications of His adorable goodness
and power, as the different phenomena of insect-life have been paraded
before us. Yet this is but a very minute portion of what really exists
of the admirable and beautiful in the insect world. Not one volume,
not a hundred volumes, would suffice to relate the interesting facts
which connect themselves in various ways with the insect's life. The
main features only have been developed, and these imperfectly. Such
being the case, what a world of wonders is the great creation, were we
to consider it only as peopled with insects! What pen could write their
history; what tongue narrate the many marvels of their existence! Ten
thousand times ten thousand, and thousand of thousands, surround us on
every side, accompany us on our excursions, and visit us in our homes,
fill the air with life, and the waters with creeping things.

The history of an insect's life impresses upon us one of the most
consoling truths contained in the word of God. We may learn from the
tale of God's wonders in the vegetable creation, we may find also in
the history of birds, beasts, and fishes, innumerable proofs of His
love, and care, and goodness to all. But these are creatures whose size
in the main renders them conspicuous; too much so, as we might say, to
be overlooked. "Ah! then,"--were there no insects, one might doubtingly
exclaim, "God may take thought for these large creatures, while more
minute beings would be beneath His notice. And so with me: God may
order and arrange the great events in my life; but are not the little
ones too small for Him to regard?" The life of an insect answers these
doubts. It tells us, that though a being be only of the size of a grain
of sand, or not larger than the full stop at the end of this sentence,
God has supplied it with the most beautiful organs; has endowed it with
life, and with the most wonderful instincts, thus manifesting that, in
the words of Scripture, "His care is over all His works." If God, then,

    "To whom an atom is an ample field,"

has not thought it beneath Him to take care for such diminutive,
short-lived creatures as these, how much more will He care for His own
people, reconciled to Him through the blood of Jesus, and sanctified
by the Holy Spirit of promise! We are not left, however, to learn this
blessed truth from the page of creation alone. Our Lord has himself
declared to us, that the very hairs of our head are all numbered, and
has left on record the promise, that if we "seek first the kingdom of
God and His righteousness, all these things," that is, all temporal
things, "shall be added unto us."

  R. E.


THE END.


R. CLAY, PRINTER, BREAD STREET HILL.




FOOTNOTES:


[A] Vide Frontispiece to this Chapter.

[B] Mr. Rennie.

[C] The definition of the words Caterpillar, Grub, Maggot, as popularly
understood, is as follows:--

A _Caterpillar_ is the larva of a butterfly, moth, or saw-fly, often
hairy, and always provided with a larger or smaller number of legs.

A _Grub_ is the larva of a beetle, having six feet and a smooth body.

A _Maggot_ is the larva of a bee, wasp, or fly, and has no legs.

[D] One of these insects which fell under the writer's notice pierced
and sucked dry aphides of several different species quite indifferently.

[E] This scene is represented in the Frontispiece.

[F] To protect the wine from them it is customary to have little silver
covers for the wine-glasses, which are put on immediately that the
glass is taken from the lips.

[G] Vide "The Life of a Tree."

[H] The insect in the act of squirting is shown in the Frontispiece to
this Part.

[I] Mr. Blackwall has discovered that by carefully examining the _feet_
of spiders, this mistake may be avoided.

[J] M. Bonnet writes of the pupa of a moth, that it can climb up and
down inside its cocoon like a chimney-sweep in a chimney! Some twirl
about inside their cocoons; and it is said that a great entomologist
was once so terrified by the curious noise thus made, that he nearly
threw down the box in which it was, in his alarm.

[K] From a Latin word, signifying "covered," or "disguised."

[L] From a Latin word, signifying "compressed into a small compass."

[M] All pupæ cannot be thus hastened or retarded by influence of
external heat or cold. The pupæ of a moth, very common in our fields,
if all exposed to the same temperature will some of them develop this
year, some the next, and some the year following. This singular fact
cannot be explained.

[N] This scene is depicted in the Frontispiece to the last Part.

[O] Now-a-days the chemist might also answer, _Gutta Percha_; for it
is a singular fact that strong acids have no action upon that curious
substance.

[P] That is, the twelfth part of an inch.

[Q] This scene is represented in the Frontispiece to Part III.

[R] See page 241.

[S] See p. 316.

[T] Several other explanations of red-rain are given, which account for
it by the presence of animalcules, fungi, &c.

[U] Vide the admirable Address of W. Spence, Esq. F.R.S. President of
the Entomological Society for 1849; p. 5.

[V] The proboscis of the carpenter-bee differs from that of the
honey-bee, possessing a curious notched sheath, as represented in the
lower cut.

[W] If we refuse to adopt Dr. Erichson's view of the use of the antennæ.

[X] This plant is a native of South Africa, and a fine specimen of it
exists in the conservatories at Kew. Its botanical name is _Stapelia_.

[Y] The writer has repeated these experiments in a number of cases, and
finds their accuracy confirmed. By cutting off one of the poisers, the
fly is partly crippled, and has a disposition to spin round in flying;
by cutting off both, it is quite unable to fly at all, and becomes
instantly sensible of the loss of apparently a most important pair
of organs, by being so tame as not to try to escape from a touch. A
"Father Long-legs" thus treated had a tendency to fall head foremost,
and also to lie on its back.

[Z] The writer is responsible for these experiments.

[AA] See p. 160.


Transcriber's Note

All paragraphs split by illustrations were rejoined. All obvious
typographical anf formatting errors were corrected.