LITTLE BLUE BOOK NO. =796=
Edited by E. Haldeman-Julius

Life Among the
Butterflies

Vance Randolph, B. Sc., A.M.

Drawings by Peter Quinn


HALDEMAN-JULIUS COMPANY
GIRARD, KANSAS




Copyright, 1925,
Haldeman-Julius Company.


PRINTED IN THE UNITED STATES OF AMERICA




LIFE AMONG THE BUTTERFLIES




CONTENTS


  Chapter I. Books About Butterflies            7

  Linnaeus--Clerck--Fabricius--Peter Cramer--Hübner--Smith
  and Abbot--Boisduval and
  LeConte--Harris--Morris--W. H. Edwards--S.
  H. Scudder--G. H. French--C. J. Maynard--W.
  J. Holland--William G. Wright--Longstaff--C.
  M. Weed.

  Chapter II. The Butterfly’s Body            12

  The Head, Eyes, and Mouth Parts--The Thorax,
  Wings, and Legs--The Abdomen--The Digestive
  Apparatus--The Circulatory System--The
  Respiratory Tract--The Excretory Organs--The
  Nervous System--The Reproductive Organs.

  Chapter III. Butterfly Metamorphosis            19

  The First Stage or Egg--The Second or Larval
  Stage--The Third or Pupal Stage--The
  Fourth Stage or Imago.

  Chapter IV. The Case of the Red Silverwing          23

  Oviposition--The Egg--The Emergence of the
  Caterpillar--The Caterpillar--Moulting--Pupation--The
  Chrysalis--Pupal Movements--The
  Appearance of the Butterfly.

  Chapter V. The Classification of Butterflies          33

  Subkingdoms, Classes, Orders and Suborders--The
  Four Families--Subfamilies, Genera, and
  Species--The Value of Scientific Nomenclature--Varieties.

  Chapter VI. The Four Families          38

  The Four-footed Butterflies--The Euploeinae--The
  Heliconiinae--The Nymphalinae--The
  Satyrinae--The Libytheinae--The Gossamer-winged
  Butterflies--The Lycaeninae--The Swallowtails
  and their Allies--The Pierinae--The
  Papilioninae--The Skippers.

  Chapter VII. Enemies and Protection            55

  Protective Coloration--Offensive Odors and
  Tastes--Warning Coloration--Protective Mimicry--Heliotropism
  and List--Feigning Death.




LIFE AMONG THE BUTTERFLIES




CHAPTER I

BOOKS ABOUT BUTTERFLIES


Many ancient and mediaeval writers dealt with butterflies, but the
first descriptions of American species are found in the works of
Linnaeus, the great Swedish naturalist who wrote about 1750, and
invented the system upon which all modern classification is based.
Pictures of several American butterflies were published in 1759 by
Charles Clerck, who had studied with Linnaeus.

Johann Christian Fabricius, a professor at the University of Kiel,
published a few more descriptions in 1796, and Peter Cramer, at about
the same time, brought out four large volumes on the butterflies of
Asia, Africa, and the Americas. Most of these early books were written
in Latin, and are now so rare and expensive that few American students
have ever seen them.

Jacob Hübner published his great volumes on exotic butterflies in the
early part of the nineteenth century. This work was written in German,
and contained more than six hundred colored plates, but a good copy now
costs about eight hundred dollars, and is of very little use anyway.

In 1797 Sir James Edward Smith brought out his two-volume work on _The
Natural History of the Rarer Lepiodopterous Insects of Georgia_, the
first books ever devoted exclusively to North American species. This
work is valuable chiefly because it contains some drawings by John
Abbot, an Englishman who had actually lived in Georgia and studied
moths and butterflies at first hand. Some of Abbot’s pictures were
later used in another work on American lepidoptera by Dr. J. A.
Boisduval of Paris, and Major J. L. LeConte of New York, who wrote
in French about 1833. The books of both Smith and Boisduval are now
practically unobtainable.

In 1841 the Biological Survey Commission of Massachusetts published
a report on injurious insects by Dr. Thaddeus William Harris, which
described many New England butterflies. It is now out of print, the
last edition appearing in 1862.

The Rev. John G. Harris brought together a deal of information from the
works of other writers, and made a few minor observations of his own;
his compilation was published by the Smithsonian Institution about 1860.

In 1868 William H. Edwards, an engineer who lived in Coalburg, West
Virginia, brought out the first volume of his famous work, _The
Butterflies of North America_--probably the best book on the subject
ever written. Edwards laboriously worked out the life-histories of many
species, and illustrated the work by careful drawings and paintings
of his own. Two more volumes appeared later, the last one published
in 1897. _The Butterflies of North America_ is a magnificent piece of
work, produced under all sorts of handicaps, and will always be a
classic to American students of the subject.

In 1886 Dr. Samuel Hubbard Scudder published his _Butterflies of New
England_ in three volumes; this monograph is superbly illustrated, and
compares very favorably even with the epoch-making work of Edwards. The
works of Edwards and Scudder are probably the best books on butterflies
ever written in any language, and must always remain as monuments
of American industry and scholarship. Because of the excessive cost
of reproducing the colored plates, however, they are both rather
expensive; Scudder’s work retailed at ninety dollars, while Edward’s
three volumes never sold for less than a hundred and fifty, and even
this price, according to Dr. W. J. Holland, was below the cost of
manufacture.

_The Butterflies of the Eastern United States_, by G. H. French,
appeared about 1886. It is a good little book, and is still in common
use, but the illustrations are few and unsatisfactory.

In 1891 C. J. Maynard published a _Manual of North American
Butterflies_ with ten colored plates; the plates are very poor indeed,
and the text not much better.

In 1893 Dr. Samuel Hubbard Scudder, the author of the three great
volumes on the New England species, brought out a little book called
_The Life of a Butterfly_. It is a brief and popular account of the
life-history of _Anosia plexippus_, the Monarch or Milkweed butterfly,
which is common everywhere. Dr. Scudder’s _Brief Guide to the Commoner
Butterflies of the Northern United States and Canada_ also appeared in
1893--a very useful little book.

In 1898 Dr. W. J. Holland, Director of the Carnegie Museum at
Pittsburgh, published his famous _Butterfly Book_, in which he
described more than five hundred species, accompanying each description
with a sketch of the life-history and habits in all cases where these
details were known. The magnificent colored photograph plates are
quite equal for all practical purposes to the hand-colored drawings of
Edwards and Scudder, and enable the veriest tyro to classify any of
the commoner butterflies simply by comparing them with the pictures.
Besides the detailed description of each species there is a great
deal of miscellaneous information of interest to the general reader.
Because of the new process of reproducing photographs in colors the
book sold very cheaply--never more than four or five dollars--and has
done more to arouse a popular interest in butterflies than all other
works together. Many of the elementary books since 1898 are indebted to
Holland’s book, and the present booklet is no exception.

In 1905 William Greenwood Wright of San Francisco, published a book
called _West Coast Butterflies_. This work is illustrated with colored
plates nearly as good as Holland’s, and is indispensable to those
interested in California species.

George B. Longstaff’s _Butterfly-Hunting in Many Lands_ appeared in
1912. The book itself is of no great interest to North Americans,
as Longstaff spent only two weeks here, and came no farther south
than Montreal. Still, his chapter of _Bionomic Notes_ deals with
butterflies in general and is well worth reading. The best part of
the book, however, is the appendix, which contains E. A. Elliott’s
translations of Fritz Müller’s famous papers on scent-producing organs
in butterflies. The most important of these had never been published
except in some obscure Portuguese journals, practically inaccessible to
the American student.

In 1916, encouraged by the success of his _Butterfly Book_, Dr. Holland
prepared a pocket manual called the _Butterfly Guide_, with colored
figures representing some two hundred and fifty species.

In 1917 there appeared Clarence M. Weed’s _Butterflies Worth Knowing_,
with thirty-two plates in color. This is one of the best of the smaller
popular books, and contains a great deal of valuable modern material,
but is not to be compared with Holland’s work.

No important popular books on butterflies have appeared in recent
years. The best single work for the general reader is still Holland’s
_Butterfly Book_; those living west of the Rockies should have Wright’s
_West Coast Butterflies_ also.




CHAPTER II

THE BUTTERFLY’S BODY


The body of a butterfly, like that of any other insect, is divided by
constrictions into three parts: the head, the thorax, and the abdomen.
The head carries the eyes, antennae, and mouth parts; the thorax bears
the legs and wings; and the abdomen the sexual appendages.


THE HEAD, EYES, AND MOUTH PARTS

The _head_ is globular, usually a little flattened from front to rear.
Two large _compound eyes_ are located at the sides of the head, and the
face or front consists largely of a plate called the _clypeus_. Above
the clypeus and between the eyes are the _antennae_ or feelers, which
are believed to be the organs of hearing, smell, and touch. Below the
clypeus is the _labrum_ or upper lip, and the rudimentary _mandibles_;
just below these are the two _maxillae_, which unite to form a tube
called the _proboscis_, used in sucking nectar out of flowers. When not
in use the proboscis is coiled up like a watch-spring between the two
three-jointed _labial palpi_. The _labium_ or lower lip is very small
in butterflies.


THE THORAX, WINGS AND LEGS

The _thorax_ is composed of three segments, the front part or
prothorax, the middle part or mesothorax, and the hind part or
metathorax. The _prothorax_ bears the front legs; the _mesothorax_ the
second pair of legs and the fore wings; the _metathorax_ carries the
third pair of legs and the hind wings. The under side of the thorax
is called the _pectus_ or breast. The large muscles which operate the
legs and wings are contained in the thorax. One pair of _spiracles_ or
breathing-holes is found in the prothorax; the other seven pairs are
located in the abdominal segments.

The butterfly has four _wings_, which are the largest and most
conspicuous part of the insect. The wings consist of membranes
stretched over horny tubes called veins; in the newly emerged insect
the veins contain both blood and air, but the veins of the adult
contain air only. The colors of the wing are due to minute _scales_
which cover the membranes in an overlapping fashion like shingles on
a roof. The scales vary considerably in size and form as well as in
color, and the males of some species bear specialized scales known as
_androconia_, which produce odors attractive to the females. The third
of the wing nearest the body is the _base_; the middle part of the
wing is the _median_ or _discal_ area; the outer portion is called the
_limbal_ area. The front edge is the _costal margin_; the outer edge
is the _external margin_; the posterior edge is known as the _inner
margin_. The angle of the outer and inner margins of the front wings is
called the outer angle, and the corresponding angle of the hind wings
is the inner or anal angle. The outmost tip of the front wing is called
the _apex_.

The fore wing has three simple veins: the _costal_, the _radial_, and
the _submedian_. There are also two branching veins, the _median_
and the _subcostal_. The median vein has three branches or nervules,
while the subcostal usually has four or five. The hind wing has five
simple veins: the _costal_, _subcostal_, _upper radial_, _lower
radial_, _submedian_, and _internal_. The costal vein in the hind wing
usually has a short ascending spur called the _precostal_ vein but it
is classed as a simple vein none the less. The median vein has three
nervules, as in the fore wing. In both fore and hind wings, between
the subcostal and median veins, there is an area called the _cell_,
which is often closed or partially closed on the outer side by three
_discocellular veins_, designated as upper, middle, and lower.

Each of the six _legs_ is divided into five parts. The section
nearest the body is the _coxa_, which is attached to the ring-like
_trachanter_. Next beyond the trachanter is the _femur_, then the
_tibia_, and finally the _tarsus_ or foot bearing the tarsal claws,
which are used in clinging to various objects when the butterfly is at
rest. In some species the fore legs are small and quite useless, a fact
which is used in classification.


THE ABDOMEN

The _abdomen_ is composed of ten segments; the first seven bear
_spiracles_ or breathing-holes (completely hidden by scales, however)
and the last two segments are modified to form external sexual
appendages. In the male there is a pair of _claspers_ for holding the
female during copulation; in the female there is only a short and
simple _ovipositor_.


THE DIGESTIVE APPARATUS

The _alimentary canal_, the principal part of the digestive apparatus,
is a tube extending through the entire body from the end of the
proboscis to the anal opening. Just above the proboscis is a _bulb_,
which is enlarged by the contraction of muscles attached to the hard
parts of the head. When the bulb is expanded nectar may be sucked up
through the proboscis; then the valve at the end of the proboscis is
closed, and the bulb contracted again. By this means the liquid is
forced back into the _esophagus_ or gullet, and hence into the _crop_.
Just behind the crop is the _stomach_, and just behind the stomach is
the _small intestine_. From the small intestine the part of the liquid
not absorbed flows into the _large intestine_, which is divided into a
front part or _colon_, and a rear and lower part called the _rectum_.
From the rectum the fecal matter passes out of the body through the
_anal opening_.


THE CIRCULATORY SYSTEM

The _circulatory system_ consists essentially of a single blood vessel,
running the entire length of the body in about the position occupied
by the spinal column in the higher animals. This tube is open at the
rear, and has valves opening inward all along its sides. In the thorax
there is a pulsating enlargement which serves as a simple _heart_.
The _blood_ is a colorless liquid which percolates about through the
entire body cavity, not being confined to any particular arteries or
veins. It is ultimately collected into the dorsal blood vessel, and
the pulsating heart keeps it moving, so that it absorbs food from the
stomach and intestines, and distributes it to the various parts of the
body.

[Illustration: Fig. I.--Diagram showing internal structure. 1,
proboscis; 2, bulb; 3, brain; 4, heart; 5, crop; 6, dorsal blood
vessel; 7, small intestine; 8, colon; 9, rectum; 10, anal opening; 11,
Malpighian tubule; 12, stomach; 13, ventral nerve cord; 14, esophagus;
15, subesophageal ganglion.]


THE RESPIRATORY TRACT

Insects have no lungs, and the blood does not carry oxygen about as
in the higher animals; air is drawn into the body and brought into
direct and immediate contact with the tissues. In the butterfly there
are eight pairs of _spiracles_ or breathing-holes--seven pairs in the
abdomen and one in the prothorax. These spiracles are connected with
large _air-sacs_ reaching from one end of the body to the other, each
air-sac being provided with minute branching tubes called _tracheae_,
which carry air directly to the various tissues of the body. The carbon
dioxide produced in the respiratory changes passes out through the
spiracles, the transfer of gases being produced largely by movements of
the abdominal muscles.


THE EXCRETORY ORGANS

The abdomen of the butterfly contains a number of slender _Malpighian
tubules_, in contact with the blood contained in the various cavities.
These tubules extract waste matter from the blood, functioning just
as kidneys do in the higher animals. The butterfly has no bladder
or urethra, however; the Malpighian tubules empty into the small
intestine, and the urine passes out of the body with the fecal matter.


THE NERVOUS SYSTEM

The nervous system consists of the brain, the subesophageal ganglion,
and the ventral nerve cord, together with branches of these structures.
The _brain_ is a large mass of nerve tissue in the head just above the
esophagus. The two _optic nerves_ which supply the large compound eyes
make up the principal part of the brain, being much larger and more
complicated than the _cerebrum_, which is supposed to be the organ of
sensation.

The _subesophageal_ ganglion is a sort of second brain lying just below
the esophagus; it gives off nerves which supply the mouth parts and
control the mechanism of feeding. The _ventral nerve cord_ runs back
from the subesophageal ganglion and traverses almost the entire length
of the body, being analogous to the spinal cord of the vertebrates.
It bears three _ganglia_ in the thoracic region which give off nerves
to the legs, wings, and thoracic muscles. Other ganglia, located in
the abdomen, have many branching nerves which are distributed to the
abdominal muscles and the viscera.


THE REPRODUCTIVE ORGANS

The _ovaries_ in the female butterfly are sometimes so large as to
crowd the other organs in the abdominal cavity. They communicate by
means of tubes called _oviducts_ with the _copulatory_ apparatus at
the end of the abdomen. The _testes_ of the male butterfly are usually
combined into a single organ; they discharge the _seminal fluid_ into
the _vas deferens_, whence it is conducted to a sort of pouch near the
penultimate segment of the abdomen. In copulation the ends of the male
and female abdomens are locked together by certain clasping appendages,
and the seminal fluid of the male is forced into the body of the
female, where it meets and fertilizes the eggs as they descend from the
ovaries.




CHAPTER III

BUTTERFLY METAMORPHOSIS


Some insects, grasshoppers for example, pass through an _incomplete
metamorphosis_; that is, the young grasshopper is very much like its
parents except as regards size. This is the same sort of development
found among birds, reptiles, and other vertebrates. The egg of a
butterfly, however, does not hatch into a miniature replica of its
parents, but into an altogether different sort of creature, which must
pass through a _complete metamorphosis_ before it becomes a butterfly.
To put the matter briefly, there are four distinct stages in the life
of a butterfly: the egg, the caterpillar, the chrysalis, and the imago,
or butterfly proper.


THE FIRST STAGE OR EGG

Female butterflies are equipped with organs called ovaries which
produce ova, and male butterflies have testes which produce sperm. By
an act called copulation (in which the male and female abdomens are
locked together by appropriate appendages) the sperm of the male is
introduced into the body of the female. A single spermatozoon fuses
with each ovum, and the result is a fertilized egg. The female deposits
the egg upon a green leaf, and as a rule each species is limited to one
or two particular kinds of plants. Butterfly eggs are small, but always
large enough to be seen with the naked eye, and they vary widely in
shape and color as well as in size.


THE SECOND OR LARVAL STAGE

[Illustration: Fig. II.--The Viceroy (_Basilarchia disippus_), an
example of the family Nymphalidae, or four-footed butterflies. This
is the butterfly that mimics the Monarch; see section on Protective
Mimicry. A, egg; B, caterpillar; C, chrysalis; D, imago.]

Most butterfly eggs hatch within a week or two, producing worm-like
larvae called _caterpillars_, which differ in appearance according to
the species, but whose general characteristics are well known. The
principal business of a caterpillar is to eat; no sooner has it emerged
from the egg than it devours the egg-shell, and then sets to work on
the leaves of the food plant. Its growth is so rapid that the outer
skin must soon be shed, and this shedding process is known as moulting.
Most caterpillars moult about four times. The caterpillar stage
usually lasts only a month or so, but there are a few species which
hibernate and spend the winter as caterpillars.


THE THIRD OR PUPAL STAGE

When the caterpillar is fully grown it spins a little silken button
on some solid object, hangs itself up by the tail, and undergoes a
final moult. When the old skin peels off this time it reveals, not a
caterpillar with a bright new skin, but a different sort of creature
altogether. The apparently lifeless pupa or _chrysalis_ shows some of
the characteristics of a butterfly, but the wings and legs are folded
up, the antennae are cemented fast against the body, and the whole
structure covered by a horny, tight-fitting sheath. This state of
affairs usually lasts only three or four weeks, but some butterflies,
particularly in temperate climates, pass the winter in the pupal state.


THE FOURTH STAGE OR IMAGO

When the chrysalis stage is over the outer skin bursts open about the
head, and the _imago_--the butterfly proper--crawls out. The newly
emerged butterfly is a sorry-looking specimen; the wings are very
small and flaccid, and it can do no more than cling to some convenient
support, usually the empty skin of the chrysalis. After a while,
however, the body juices flow out into the wings, which expand and
harden, and in a few hours the young butterfly is flitting from flower
to flower with its fellows.

Ordinarily the imago does not live long--often only a few days. Just
as the caterpillar’s sole business is to eat, the mature butterfly has
only one important function, and that is reproduction. It speedily
finds a mate (that’s what its wings are for), contributes its quota of
ova or sperm to produce another generation of caterpillars, and its
ephemeral existence as a butterfly is over.




CHAPTER IV

THE CASE OF THE RED SILVERWING


Having dealt briefly with the transformations of butterflies in
general, it may be well to examine more closely into those of a
single representative species. For this purpose I have chosen _Dione
vanillae_, known as the Red Silverwing, and have described each stage
and transition in considerable detail. The following paragraphs are
extracts from the daily records of a study I made in southern Kansas,
the northern limit of _vanillae’s_ usual range.


OVIPOSITION

“One of the females, alighting upon the upper side of a leaf within
ten inches of my face, suddenly elevated the forward part of the body,
brought the wings together vertically, curved the abdomen slightly
forward, and drew its tip slowly across the surface of the leaf for a
distance of approximately 12 mm. Remaining quiet for an instant, it
lifted the abdomen, showing an egg firmly attached to the leaf. The
eggs are laid singly, usually in the upper middle of the leaf. I have
never seen more than one upon the same leaf.”


THE EGG

“The egg measures about 1.12 mm. in height and .7 mm. in diameter
at the widest part, barrel-shaped, with fourteen vertical ribs. A
brilliant yellow at first, it assumes after about thirty-six hours a
reddish brown color. A few hours later an irregular, whitish broken
ring, not quite circling the egg, appears about one-third of the
distance from the top. When within an hour or so of hatching the shell
becomes very thin and transparent and reflects the light with a sort of
frosted-glass effect. The large black head of the larva inside gives
the upper one-third of the egg a black, metallic appearance, while the
yellowish body may be seen curled up in the lower part. The incubation
period seems to vary greatly with the temperature, from forty-seven
hours to seven days.”


THE EMERGENCE OF THE CATERPILLAR

“At 2:15 p. m. the larva was clearly visible through the shell. Slight
bodily movements were noted, then the very large, shining black head
was thrust out at a point on one side of the egg, just below the top.
The entire structure rocked and swayed slowly back and forth, inclining
toward the side from which the head projected.

“At 2:19 the larva emerged very slowly, head first. The head and the
final segment appeared very large. The entire length was about 1.5
mm. The body yellowish red; prolegs and caudal segment lemon yellow;
the head, legs and spines black. The latter bear no visible branches,
and appear as stiff, black hairs, each growing out of a slight black
protuberance.

“The beautiful egg-shell remains erect, the form being unchanged.
There is a ragged hole in it, but it is scarcely noticeable, and
appears hardly large enough for the egress of the caterpillar.”


THE CATERPILLAR

“The newly emerged larva does not venture far from the egg-shell and
does not move about much for the first five or six hours. It sometimes
devours the shell, but this is not usually the case. At the age of six
hours it appears darker, and the black spots from which the hairlike
spines protrude have become more conspicuous. Has not eaten any of the
leaf, and has increased in size very little if at all.”

“At the age of twenty-seven hours the larva attains a length of 2.3
mm. and has eaten several small holes in the center of a large leaf,
gnawing through the leaf to the transparent epidermis on the opposite
side, which is left intact. Usually works from the upper side, but by
no means invariably.”

“These smaller larvae seem to be always attached to the leaf with silk,
although the threads are very few and fine. More mature larvae feed
differently; they grip the petiole with the prolegs, and eat from the
edge inward and forward, swinging the head toward the midrib, with
practically no lateral motion.”

“The caterpillar is cylindrical and bears six rows of black, branching
spines, twelve in each row. As regards color, there are besides the
reddish, newly hatched creature described above, two well-defined
types: the orange-drab and the drab-orange. In the first the body
appears orange with three narrow drab stripes, and a very narrow
lateral line just above the prolegs. In the second the drab markings
become very much more prominent, so that the body now appears drab with
four narrow orange stripes. The narrow drab dorsal line of the younger
caterpillar becomes very conspicuous in the mature larva, separating
the dorsal surface into two distinct orange areas. As the orange-drab
type seems to embrace all of the smaller larvae, and as all those about
to pupate belong to the drab-orange type, I have assumed that the color
change is a matter of maturity.”


MOULTING

“1:30 a. m.--Larva about 21 mm., inactive and very dark, extended
on lower side of leaf, front of body high, head bent, holding with
third, fourth and anal prolegs. A few silk threads lie flat on leaf
near caudal end of body. After some little rippling of muscle (no
violent motion) the skin of the body separates from that of the head.
The former is very tight; slowly, segment by segment, it is skinned
backward until finally it is left, a crumpled, prickly black ball
about 4 mm. in diameter, fastened to the leaf by the aforementioned
silk. Meanwhile the head covering, which is all of a piece and bears
two large spines, slips forward until it appears to be held in the
mandibles as a hat might be held between the teeth. After a moment
it falls to the ground. The caterpillar now appears somewhat short
and a trifle thickened. The head, legs and prolegs are yellow,
the body orange. The spines are only half size, blunt, yellow and
semi-transparent. The branches appear as black hairs lying flat along
the sides of the spines.”

“11:33 a. m.--The spines have now attained practically their normal
size, springing out with astonishing rapidity. They are still blunt,
yellow and semi-transparent, but the black branches have reached normal
size and assumed their proper position. The two head spines, which were
curled backward, have taken on the usual angle. The head, body and
prolegs now appear orange rather than yellow, the head being lightest.
The drab dorsal stripe has appeared, but is very narrow. The row of
depressions, one in the dorsal center of each segment, is much more
conspicuous than usual.”

“11:50 a. m.--Appears quite normal again, except that the spines are
not quite as black, showing grayish toward the tips. The black frontal
markings appear. Caterpillar rests motionless.”

“12:10 p. m.--Turns about and begins to devour the cast-off skin. With
the lens I watched it begin at the tip of one of the big spines and
consume it clear to the root, apparently in about three mouthfuls. The
head covering is never eaten.”

“12:30 p. m.--Skin practically consumed. Larva rests motionless, a few
of the surplus spines resting beneath the head and thorax.”


PUPATION

“10:00 a. m.--Caterpillar, 37 mm. long, leaves food plant and begins
to wander restlessly about.

“1:00 p. m.--Extended motionless, clinging to under side of window
frame.

“2:30 p. m.--Same position.

“3:30 p. m.--Begins to lay a sparse, ragged network of very fine
threads flat to the surface, covering a space of perhaps an inch
square. These threads become thinner toward the periphery of the net,
where they are hardly visible without a lens.

“4:00 p. m.--Spins a little white silk button in the center of the
network. The head moves slowly out horizontally in all directions from
the button about one-half inch, swinging always back to the center. The
body is fully extended, the abdomen being away from the button.

“4:30 p. m.--Interrupted the button-making to raise high the caudal
third of the body, spreading the anal appendages apart several times.
When a pellet of excrement appeared, the caterpillar turned about and
pulled it out of the anal opening with the mandibles, holding it thus a
moment before allowing it to fall to the floor.

“4:45 p. m.--Resting, body extended, clasping the button with the third
prolegs.

“6:00 p. m.--Fastened to the button. The body is extended horizontally,
clinging to the under surface of the window frame with the prolegs;
head drawn back, legs not touching the surface.

“8:00 p. m.--Hanging from the button. The body is thickened a trifle
and shortened to 31 mm. Color much lighter; hangs motionless except
for very slight movements of the legs and prolegs.”

“9:00 a. m.--No change.

“10:00 a. m.--The brilliant colors have practically disappeared,
leaving the body a pearl-gray color, against which the black spines
show up with startling distinctness. Movements slight and infrequent.
The dorsal thorax is now the lightest part of the body.

“11:00 a. m.--Begins to wriggle a little.

“11:10 a. m.--I note that the spines appear closer together at the
caudal end of the body; then see that the skin has split down the back
and that the light-colored head of the chrysalis is protruding. By a
series of vigorous wrigglings the skin is slowly forced up to where the
tip of the abdomen is attached to the button. Then comes the violent
struggle which finally loosens the skin, which hangs for a moment
against the ventral abdomen, then falls to the floor. The entire moult
is complete in less than five minutes.”


THE CHRYSALIS

“When the chrysalis first appears it is nearly cylindrical; no dorsal
depression, no ventral bulge. The head is bent forward, and the whole
thing has a compact, slug-like appearance. An hour or so later the
head is no longer bent, and bears two double projections, set wide
apart; the wing cases are bulging and prominent; on the dorsal side,
opposite the middle of the wing covers, is a U-shaped depression; there
are projections on the third, fifth, sixth, and seventh abdominal
segments, those on the third being the largest. At first the head,
thorax and wing covers are translucent and nearly white; the abdomen
is a little darker and bears a ventral bluish stripe on the fourth,
fifth and sixth segments. The four pairs of dorsal protuberances are
amber-colored.

“An hour later the head and thorax darken somewhat, and opaque whitish
veins appear in the wing covers. Distinct black lines mark the outer
borders of the fore wings, and a black V-shaped mark shows the position
of the larger of the three discal spots.

“Another hour and the translucent appearance is gone, the abdomen and
the dorsal thorax become much darker, the wing covers grayish tan,
while the bluish ventral stripe turns gray or white.

“From this time forward the chrysalis does not change appreciably
in form or color (although the latter varies greatly) until about
twenty-four hours before the emergence of the butterfly, when the
entire body becomes very dark.

“The average length of the chrysalis is 28 mm., and the white ventral
stripe is usually the most conspicuous marking. After the butterfly
has emerged the color variations of the chrysalis still persist in the
empty shells, some being much darker than others.

“Not infrequently the cast skin of the larva is found attached to the
anal portion of the chrysalis. This skin is black excepting the head,
which is gray, and the black branching spines loom large because of
the contraction of the empty skin.

“Sometimes the chrysalids turn bright yellow; these are usually
infested by parasites. I have opened many of these pupae, but have
never found the parasitic larva itself; the pupae and adults I have
often taken, the latter being a small (2.3 mm.), green hymenopterous
insect which I have not as yet had the opportunity to classify. Some
ten or a dozen of these insects emerge from a small round hole, usually
in the wing cover, in early August.”


PUPAL MOVEMENTS

“The chrysalis seems unable to bend the body toward the back or toward
the wing covers; sidewise, however, it can turn until the body is
extended nearly parallel to the horizontal surface from which it is
suspended. Six chrysalids which hung in a north window in September,
1919, and which I observed for fourteen days, were noted to be
invariably and unanimously pointed inward (toward the warm room, that
is) every morning. During the warmer part of the day there was no
uniformity in position. Six specimens--fourteen days; it appears to be
more, perhaps, than mere coincidence. The pupal sensibility to light
and temperature stimulii should be worth investigation.”


THE APPEARANCE OF THE BUTTERFLY

“Two or three weeks after pupation (the period varies with the
temperature, from eight days in August to twenty-seven in November)
the chrysalis turns nearly black, and a diagonal fissure appears on
either side, extending from the back of the head down along the antenna
cases, nearly to the middle ventrum.

“About twelve hours later, after some little wriggling, the ventral
triangle formed by the covering of the head, antennae and mouth parts
falls open trap-door fashion, the antennae covers serving as hinges and
the flexing point being about one-third of the distance up the wing
covers from the abdomen. There is also a dorsal cleavage following
the medial dorsum to the first abdominal segment, then the outline of
the wing covers to a point half way to the end of the antenna covers.
The crumpled-winged imago wriggles out and mounts the empty shell, to
which it clings by the four hinder limbs, turning the entire body back
and forth as if mounted on a pivot. In each of these turns the body
describes an arc of nearly 90 degrees, the body being held stiff. The
angle of the body is about 45 degrees from the vertical, the head being
uppermost. The proboscis is usually partially unrolled. In five or six
hours the soft, wrinkled wings spread and harden, and the insect is
able to fly. A thin, transparent liquid, and sometimes a thick, reddish
substance, are voided by the newly emerged butterfly.”




CHAPTER V

THE CLASSIFICATION OF BUTTERFLIES


In every science it is necessary to manipulate a large number of
related facts, and this cannot be done unless the data are arranged
in some systematic and orderly fashion. In order to make use of the
facts about butterflies, one must know something of the relation of one
butterfly to another, and the relation of butterflies in general to the
rest of the animal kingdom.


SUBKINGDOMS, CLASSES, ORDERS, AND SUBORDERS

Members of the animal kingdom which have no spinal column, but only
an external skeleton composed of horny rings, are assigned to the
subkingdom _Arthropoda_. Arthropods which have six legs are grouped
together in the class _Insecta_. Insects with scales on their wings are
assigned to the order called _Lepidoptera_. This order is divided into
two suborders, the _Rhopalocera_ or butterflies and the _Heterocera_
or moths. Butterflies fly in the daytime, and have slender antennae
with club-like knobs at the ends; moths are usually nocturnal or
crepuscular, and their antennae are not knobbed, but are thread-like,
feather-like, or hooked at the extremity.


THE FOUR FAMILIES

The suborder Rhopalocera is divided into four families: the
_Nymphalidae_, the _Lycaenidae_, the _Papilionidae_, and the
_Hesperiidae_.

The _Nymphalidae_ or four-footed butterflies make up the largest
family; the first pair of legs are much smaller than the others, and
are quite useless for walking. Most of the Nymphalidae are large or
medium-sized butterflies. The caterpillars are usually provided with
spines or fleshy protuberances, and the chrysalids are always suspended
by the tail.

The _Lycaenidae_ or gossamer-wings are the bright little butterflies
known as “blues,” “hair-streaks,” and “coppers.” The males do not use
the first pair of legs in walking, but the females do. The caterpillars
are small and usually slug-shaped, and the chrysalids are held closely
attached to some object by a girdle of silk.

The _Papilionidae_ is the family of the swallowtails and allied forms.
Both sexes use all six feet in walking. The butterflies are usually
large or medium-sized; many of the caterpillars produce disagreeable
odors; the chrysalids are suspended by the tail and provided with a
girdle of silk, but not drawn up to the surface to which they are
attached, as in the case of the _Lycaenidae_.

The _Hesperids_ or skippers are small butterflies with thick, moth-like
bodies and a peculiar manner of flight. Both sexes have six walking
feet. The caterpillars are smooth and thin-necked, with large globular
heads. The chrysalids are usually enclosed in a flimsy cocoon of leaves
fastened together with a few silk threads.


SUBFAMILIES, GENERA, AND SPECIES

Each one of these four families is divided into several subfamilies;
each subfamily is divided into several genera, and each genus is
divided into several species, all of these divisions being based on an
increasing anatomical similarity. Thus the common Milkweed Butterfly
belongs to the class _Insecta_, the order _Lepidoptera_, the suborder
_Rhopalocera_, the family _Nymphalidae_, the subfamily _Euploeinae_,
the genus _Anosia_, and the species _Plexippus_.


THE VALUE OF SCIENTIFIC NOMENCLATURE

One may well ask why we do not simply say “milkweed butterfly” and
have done with it, but this term refers merely to the fact that the
caterpillar feeds upon a certain plant, while _Anosia plexippus_
places the specimen definitely in the scientific scheme of things, and
designates important structural distinctions which have nothing to do
with milkweeds. The average American is prone to call any insect a
“bug” or “moth-miller” or some such unenlightening name, so that many
butterflies have no common English name at all, while others have many
different names which vary widely in different parts of the country.
Besides, the Greek and Latin names are understood by scientists in all
countries, and are less liable to corruption than terms taken from the
modern languages.

There are difficulties enough in the scientific nomenclature, without
complicating matters by the introduction of popular names. It is a
fixed rule in science that the first man to discover and describe a
species has the right to name it, and that whatever name he chooses
shall be used by everybody forever, but scientists are only human after
all, and are always anxious to discover new species and name them after
their friends or sweethearts. It often happens that a single species
is described independently by several authors, each of which applies a
name of his own devising; in this case the first is the real name, and
the others are called synonyms.

In writing about butterflies it is not customary to spell out the
generic name; one does not write _Dione vanillae_, but merely _D.
vanillae_. It is usual also to add the name of the man who first named
the species, so that the name becomes _D. vanillae_, Linnaeus, or _D.
vanillae_, Linn. In conversation one may omit the name of the genus
altogether, and refer to the butterfly simply as _Vanillae_. It is well
to remember that scientific Latin in this country is pronounced in the
insular fashion--that is, the words are pronounced as if they were
English.


VARIETIES

Sometimes the individuals of a species differ in different parts of
the country; these different forms are called _varieties_, and are
designated by a varietal name added to the generic and specific names.
_Papilio turnus_, Linn. is a large yellow swallowtail, but in the
southern part of its range some of the females are black. The black
female was formerly regarded as a distinct species, and Linnaeus named
it _Papilio glaucus_, but when it was reared from eggs laid by a yellow
female it was recognized as a variety, and is now known as _Papilio
turnus_, Linn., var. _glaucus_.




CHAPTER VI

THE FOUR FAMILIES


As we said in the chapter on Classification, American butterflies fall
naturally into four great groups called families: the _Nymphalidae_ or
Four-footed family, the _Lycaenidae_ or Gossamer-winged family, the
_Papilionidae_ or Swallowtail family, and the _Hesperiidae_ or Skipper
family.


THE FOUR-FOOTED BUTTERFLIES

The largest family of butterflies in America is the _Nymphalidae_, and
its members are called four-footed butterflies because the front legs
are so small as to be useless, leaving only four walking feet. Most of
the butterflies are large or medium-sized, the caterpillars are usually
provided with spines or fleshy protuberances, and the chrysalids
are always suspended by the tail. The family is divided into five
subfamilies; the _Euploeinae_, the _Heliconiinae_, the _Nymphalinae_,
the _Satyrinae_, and the _Libytheinae_.


THE EUPLOEINAE

[Illustration: Fig. III.--The Silver-Spotted Skipper (_Epargyreus
tityrus_), a typical Hesperid. A, egg; B, mature caterpillar; C, pupa
or chrysalis; D, imago.]

So far as the great majority of readers are concerned, this subfamily
includes but one species--_Anosia plexippus_, the familiar Monarch or
Milkweed butterfly, which is common every summer in every state in the
Union. The main color of the wings is bright reddish brown, but the
edges are black, and there are some white spots in the black area,
particularly in the fore wings. The pale green eggs are laid upon the
milkweed, and soon hatch into little black and white caterpillars. The
mature caterpillar is greenish yellow with black bands, and each end
of the body bears a pair of slender black “horns” or _filaments_. The
stout chrysalis is green with golden markings. This butterfly has a
bitter taste, and so is not molested by birds or insectivorous mammals.
For this reason _Anosia plexippus_ has become very abundant and spread
over a vast territory. Other butterflies which happen to resemble
it share in this protection even though they have no disagreeable
flavor, and this has given rise to the phenomena of _mimicry_, which is
discussed elsewhere in this book. Another interesting thing about the
Monarch is the fact that it does not hibernate in any stage; the eggs,
caterpillars, and chrysalids die when the cold weather overtakes them,
while the adults gather in great swarms and migrate southward, where
they breed continuously throughout the winter. With the advent of warm
weather the young southern Monarchs come north, deposit their eggs on
northern milkweed, and the cycle begins again.


THE HELICONIANS

This is a tropical subfamily, and has only one representative within
the borders of the United States. _Heliconius charitonius_, the Zebra
butterfly, is a slender, long-winged, black-and-yellow species common
along the roadsides of southern Florida. This butterfly has such an
evil taste and odor that no known animal will eat it. The eggs are
deposited upon the passion-flower vine; the young larva is hairy, but
the mature caterpillar is provided with a great number of branching
spines. The chrysalis is dark brown and of an odd shape; it makes a
peculiar creaking sound by moving its abdomen. Another interesting fact
about this Zebra butterfly is that the males are attracted to female
chrysalids, and may be seen hovering about waiting for their mates to
emerge.


THE NYMPHALINAE

This is the largest of all the subfamilies, numbering more than a
hundred and seventy species in the United States. They are mostly
large or of medium size, and include many of the commonest and most
conspicuous butterflies we have. One of the most interesting members
of this group is _Dione vanillae_, the Red Silverspot. The wings are
bright red on the upper surface, with black veins and markings; the
under side shows a spangled effect of brown and silver. The wings
are unusually long, and the butterfly has a disagreeable odor which
protects it from its enemies; these and other facts have led some
lepidopterists to class this butterfly with the Heliconians. The
eggs are reddish brown in color, and are found on the passion-vine;
the caterpillar is marked with orange and drab, and bears six rows
of branching spines. The chrysalis has an unusual form due to a
pronounced dorsal depression; it is usually a grayish tan in color.
_Dione vanillae_ is found in the whole southern half of the United
States, being especially abundant about New Orleans, and in southern
California. W. H. Edwards took a specimen at Coalburg, West Virginia,
and it has been reported from as far north as Worcester, Mass.

_Grapta interrogationis_, the Question Mark butterfly, is common in
all parts of the United States except the Pacific coast region. The
upper sides of both wings are reddish brown, spotted with dark brown
and edged with a faint violet color. The peculiar angular shape of the
fore wings, and the little tails on the hind wings, are the outstanding
characteristics of the Question Mark and its relatives. The under side
of the wings shows a mottled light brown, like a dead leaf; on the
under side of the hind wing is found the silver mark resembling a Greek
interrogation point (something like the English semicolon) which gave
the butterfly its name. The eggs are deposited on elm trees, hop-vines,
and several kinds of nettles. The caterpillar is reddish in color,
covered with branching spines. The chrysalis is brown or greenish, with
a conspicuous protuberance in the thoracic region.

_Vanessa antiopa_, the Mourning Cloak butterfly, may be remembered as
the first butterfly to be seen in the early Spring. The upper surface
of the wings is a rich reddish purple, with a yellow border and a
row of blue spots just inside it. The under side is gray, and blends
perfectly with the dead twigs upon which the butterfly is accustomed
to perch. The eggs are laid in clusters on the elm, willow, and poplar
trees; the dark, spiny caterpillars live in small colonies, and spin a
sort of web among the leaves of the food plant. The chrysalid is much
like that of the Question Mark butterfly. In the autumn the Mourning
Cloak crawls into a hollow tree or under a bit of loose bark and sleeps
all through the winter, often flying in the Spring before the snow has
melted, and long before the first leaves have appeared.

_Junonia coenia_, the Peacock butterfly, is a medium-sized butterfly
with an expanse of about two and one-fourth inches. The large
eye-spots on both wings give it a characteristic appearance, very
different from any other butterfly in this country. It occurs in all
parts of the United States, but is somewhat rare in the northern part
of its range. The dark green eggs are deposited on various kinds
of plantain; the caterpillar is dark and covered with spines; the
chrysalis generally light brown, and has a conspicuous depression in
the ventral thorax. This butterfly is conspicuous for its pugnacity; it
will drive away any other species which chances to approach, and even
dart at stones or other objects thrown in the air.

_Basilarchia disippus_, the Viceroy butterfly, looks very much like
_Anosia plexippus_ the Monarch, except for a single transverse black
band on the hind wings. The eggs are laid upon willow or poplar leaves;
the caterpillar has no spines, but there are two club-shaped appendages
just back of the head; the chrysalis is light gray with brown spots,
and has a fin-like projection on back of the thorax. The Viceroy
spends the winter in the larval state. When cold weather sets in the
caterpillar anchors a leaf to the twig by means of silken threads, then
rolls himself up in the leaf and sleeps until the following Spring.

_Chlorippe celtis_, the Hackberry butterfly, is smaller than most of
the common four-footed butterflies, its expanse being less than two
inches. The general color of the wings is gray, but the outer part of
the fore wings is black with broken rows of white spots. There is a
little red tinge about an eye-spot in the fore wing, and five such
spots are located near the outer edge of the hind wing. The female
is slightly larger than the male, and somewhat less pronounced in
color. The eggs are deposited in clusters on the hackberry trees;
the caterpillar bears a pair of antler-like appendages on its head;
the chrysalis is stockily built, with the head deeply notched. The
Hackberry butterfly is found in all the Southern States east of the
Rockies, and has been reported as far north as southern Pennsylvania.
It is double-brooded in the middle west, the last caterpillars
hibernate and do not reach maturity until the next year.


THE SATYRINAE

The members of this subfamily are medium-sized, obscurely colored,
forest-loving butterflies, conspicuous because of their peculiar manner
of flopping about in the grass and low herbage.

_Satyrus alope_, the Wood-nymph butterfly, is a medium-sized grayish
brown species, with a broad yellow band across the fore wing. This
yellow area contains two eye-spots, dark with blue centers, and in
the male there is a smaller eye-spot in the hind wing also. There is
a good deal of regional variation in this species: specimens from the
Northwest are often small and dark, with a reddish tinge on the lower
side of the wings; while in those from northern New England and eastern
Canada the yellow band is very dim, and the eye-spots are only vaguely
indicated. The eggs are barrel-shaped, and are laid upon various kinds
of grasses; the caterpillar has two slender diverging anal horns;
the chrysalis is green, with a prominent tubercle on the thorax.
The Wood-nymph is not a strong flyer, but flits about in a furtive,
moth-like fashion; if pursued it will often close the wings and fall
like a leaf into the grass. These butterflies are usually single
brooded, and pass the winter in the larval state.


THE LIBYTHEINAE

The butterflies of this subfamily are easily recognized by the very
long projecting palpi, which have the appearance of a beak or snout.
_Libythea bachmanni_, the common Snout-butterfly, is a small, reddish
brown species, with three or four white spots near the tip of the fore
wing. The eggs are found upon Hackberry leaves; the caterpillar has a
small head and two or three enlarged thoracic segments; the chrysalis
has a sharply pointed head and a conical abdomen. This species probably
spends the winter in the chrysalis condition.


THE GOSSAMER-WINGED BUTTERFLIES

The Lycaenidae is the family of delicate little butterflies known as
“blues,” “coppers,” and “hair-streaks.” Metallic blue, red, and grey
are the predominating colors, and the “hair-streaks” usually have an
orange spot on the hind wings. The males of this family do not use the
first pair of legs in walking, but the females walk with all six feet.
The caterpillars are small and usually slug-shaped, and the chrysalids
are held closely to some supporting object by a girdle of silk.


THE LYCAENINAE

_Lycaena pseudargiolus_ is the common little blue butterfly found in
every part of the United States except the far West. It is extremely
subject to seasonal and geographic variations, seven or eight distinct
varieties having been described. The wings of some specimens are almost
black, others are a very pale blue, while still others combine the blue
ground-color with a broad black border. The eggs are laid upon a great
variety of plants; the caterpillars are very small and slug-shaped,
and usually feed upon flowers instead of leaves. The caterpillar
produces a sweet liquid which attracts ants, and it is said that these
ants protect the caterpillar from minute parasitic flies which would
otherwise destroy it.

_Feniseca tarquinus_, the Wanderer, is perhaps the most interesting
of the so-called copper butterflies. The Wanderer’s wings are orange
brown, spotted with black on the upper side. It is found all over
the eastern half of the United States, extending well into the
Mississippi valley. The butterfly is remarkable in that it does not
frequent flowers, but flits about colonies of plant-lice, and lives
upon the sweet excrement of these insects. The eggs are laid among
the plant-lice also, and the caterpillar is carnivorous--the only
caterpillar in North America which feeds upon plant-lice instead of
plants. The chrysalis is small, brown in color, and bears a striking
resemblance to the face of a miniature monkey.

_Thecla melinus_, the common Hair-streak, is a dark bluish gray, with
a deep orange spot just in front of two tiny tails on the hind wing.
It is found all over temperate North America. The turban-shaped eggs
are usually deposited on the hop-vine; the caterpillar is a slug-like
creature with a small head, which can be extended to a remarkable
extent. The brown chrysalis lies close to the surface to which it is
attached, being fastened both at the tail and by a slight silken girdle
about the middle.


THE SWALLOWTAILS AND THEIR ALLIES

The family _Papilionidae_ includes many of the commonest and showiest
of our butterflies. The adults of both sexes have six ambulatory feet;
the caterpillars are elongate; the chrysalids are attached at the tail
and held in place by a silken girdle, but never fastened close to the
supporting surface, as the Lycaenids are. The Papilionidae is divided
into two subfamilies: the _Pierinae_ and the _Papilioninae_.


THE PIERINAE

This is the subfamily of the small and medium-sized butterflies, white
and yellow in color, so common about pastures and roadsides. _Pieris
rapae_, the cabbage butterfly, is one of the most familiar species.
It is a white butterfly, with one or two black dots and tips on the
fore wings. The pale yellow eggs are deposited on cabbage plants;
the smooth green caterpillar eats an enormous amount of sauerkraut
material, and turns into a gray or brownish chrysalis. This butterfly
was originally a European species; imported through some accident, it
appeared in Quebec about 1860. As early as 1868 it was common about
New York, and by 1881 had spread to all of the eastern states. In
1886 it was reported from Denver, and has since taken possession of
cabbage-fields in every part of the country.

[Illustration: Fig. IV.--The Zebra Swallowtail (_Papilio ajax_), a
typical representative of the subfamily Papilioninae. A, egg; B, mature
larva; C, pupa or chrysalis (note the silken girdle); D, imago or
adult.]

_Colias philodice_, the Common Yellow, is the butterfly seen swarming
about roadside mud-puddles in August and September. The wings are lemon
color with black borders, and in the female the borders are usually
broken by several small yellow spots. The yellow or reddish eggs are
laid upon various kinds of clover; the slender green caterpillar is
exactly the color of the leaves; the chrysalis is usually pale green
also. This butterfly is found from New England to Florida, and as far
west as the Rocky Mountains.

_Terias lisa_ is another yellow butterfly, much smaller than Colias
philodice, rarely expanding more than an inch and a quarter. The wings
are lemon yellow with black borders, subject to many minor variations.
The caterpillar feeds on clover, but the early stages of this species
have never been thoroughly studied, despite the fact that the butterfly
is common from the New England states to the Rockies.

_Terias mexicana_, the Mexican Yellow, is larger than _Terias lisa_,
and somewhat paler in color. The black borders or the fore wings are
very wide and indented, and the hind wings are pointed. Very little is
known of its early stages. It is common in Texas, Arizona, and Southern
California, and often strays much farther north. I have myself taken a
number of specimens in Kansas.


THE PAPILIONINAE

This is the subfamily of the true swallowtails, the largest and most
distinctive of American butterflies. The hind wings are prolonged into
two tail-like projections, and are characterized, by the absence of
the internal vein. The caterpillars are all provided with peculiar
V-shaped scent-organs called _osmateria_; these organs are thrust out
just back of the head when the insect is disturbed, and give off an
offensive odor, supposed to discomfit birds and other enemies.

_Papilio troilus_, the Green-clouded Swallowtail, is velvety black with
a row of yellow spots along the margin of the fore wings. The marginal
spots on the hind wing are pale green, and the whole outer half of
the hind wing is clouded with the same greenish tinge. The female
deposits her eggs on sassafras and spicebush leaves; the caterpillar
is lead-colored or greenish, with a swollen thorax bearing two large
eye-spots, and lives in a nest made of a folded leaf. _Papilio troilus_
is common throughout the Atlantic States and in the Mississippi Valley.

_Papilio turnus_, the Tiger Swallowtail, is the magnificent
yellow-and-black species found in practically every part of the United
States. In the northern portion of its range the male and female
appear very much alike, but in the South there are two distinct types
of females. One female is black-and-yellow like its northern sisters;
the other is black-and-blue, with no yellow at all except a few small
crescents in the outer border of the hind wing. The black female, was
for a long while considered a distinct species and called _Papilio
glaucus_. Later, however, it was discovered that some of the eggs
laid by the yellow _turnus_ produced the black _glaucus_ females, and
that, conversely, the eggs of _glaucus_ often produced the ordinary
yellow-and-black Tiger Swallowtail. The smooth bluish-green eggs are
usually found on the wild cherry leaves; the caterpillar is green, with
enlarged thoracic segments bearing two large eye-spots like those of
Papilio troilus.

_Papilio ajax_, the Zebra Swallowtail, is another striking member
of this magnificent subfamily. The combination of green and black
stripes, the blue and red crescents and the long tails on the hind
wings, distinguish _ajax_ immediately from any of its splendid fellows.
There are at least three slightly different seasonal varieties of this
butterfly, due probably to differences in the temperature to which
the chrysalids are exposed. The butterfly may often be seen hovering
about pawpaw bushes, upon which the eggs are deposited. The mature
caterpillar is pea-green with bands of yellow and black; the chrysalis
is green or brownish, and the last crop of chrysalids does not produce
butterflies until the following Spring. This butterfly ranges from New
England south to the Florida Keys, and west to the foot-hills of the
Rockies.

_Papilio cresphontes_, the Giant Swallowtail, is the largest butterfly
in this country, measuring nearly six inches from tip to tip. The
color is dark brown with bands and blotches of bright yellow, and
there is a red-and-blue spot on the inner margin of the hind wings.
The under side of both wings is yellow, with narrow dark brown bands.
This butterfly is very common in Florida, where the caterpillars--the
natives call them orange-dogs--do a great deal of damage to the orange
and lemon trees. Each female butterfly is known to lay a great number
of eggs, and it has been suggested that the ravages of the orange-dog
may be checked by shooting the butterflies on the wing with miniature
shotguns. In recent years the species has extended its range northward,
and has become quite common in the Middle West; a number of specimens
have been taken in New England, and even in Canada. In the northern
part of its territory there are no citrus trees, but the caterpillar
feeds well enough upon prickly ash and several kinds of poplars.


THE SKIPPERS

The _Hesperiidae_ or Skipper family includes all the large bodied,
small-winged, moth-like butterflies, called Skippers because of
their jerky, erratic manner of flight. They are mostly small, dull
colored butterflies with short, hooked antennae. The caterpillars are
recognized by their large heads and small necks, and usually live in
nests made of leaves fastened together with silk. The chrysalids are
rounded and moth-like, and (unlike all the other families) are usually
enclosed in a loose cocoon of silk. The classification of Skippers is a
complicated business; the Hesperiidae is the only family in which the
beginner will find it difficult to identify his specimens.

_Epargyreus tityrus_, the Silver-spotted Skipper, is the largest member
of the family, with an expanse of about one and three-fourths inches.
The general color is dark brown, with yellowish spots; the common name
is derived from the silver area on the lower surface of the hind wing,
which shows when the insect is at rest. The caterpillar is yellowish
green, with a dark brown head; it feeds upon the leaves of the locust
and other leguminous trees. When the caterpillar is mature it leaves
its hammock in the locust tree and builds a light silken cocoon upon or
near the ground. The Silver-spotted Skipper is found in nearly every
part of the United States.

[Illustration: Fig. V.--The Cabbage Butterfly (_Pieris rapae_). This
butterfly was brought over from Europe about 1860, and has spread to
every part of the United States and Canada. A, egg; B, caterpillar; C
chrysalis; D, imago.]

_Atalopedes huron_, the Sachem Skipper, is a little golden brown
species, with an expanse of a little more than an inch. The male has a
darker area in the center of the front wing, while in the female the
fore wing is marked by several small white spots. When at rest this
skipper and its near relatives usually elevate the fore wings and
depress the hind wings, an attitude characteristic of this group. The
dark, cylindrical caterpillar feeds upon various grasses: the chrysalis
is slender, with a little swelling upon the thorax, and the tongue
sheath is free as in the pupae of moths. The Sachem is known from New
York to Florida, and as far west as eastern Colorado.

_Ancyloxipha numitor_, the Least Skipper, is the smallest butterfly
within our borders, measuring often less than three-fourths of an inch
from tip to tip. The slender body and hookless antennae distinguish it
from all other skippers. The general color is bright reddish brown,
the hind wings being particularly brilliant, and surrounded by a
darker border. Its flight is weak and wavering, and it rests often
among grasses at the edges of creeks or swamps. The yellow eggs are
laid on grasses; the tiny yellow caterpillar has a black head and a
body covered with bristles, and lives in a rolled-up blade of grass.
The chrysalis is reddish, with small black dots. The Least Skipper is
widely distributed everywhere east of the Rocky Mountains.




CHAPTER VII

ENEMIES AND PROTECTION


Butterflies have many enemies. Even the eggs of butterflies are often
discovered by tiny, four-winged parasites, which pierce the egg-shell
and deposit their own microscopic eggs inside. These eggs produce
little grubs, which devour the contents of the butterfly’s egg, so that
the latter develops into a caterpillar.

The chief enemies of the butterfly tribe, however, are the
insectivorous birds, whose summer food often consists largely of
caterpillars. Caterpillars are also attacked by wasp-like parasites
which deposit their eggs in the victim’s skin; when the eggs hatch
the parasitic grubs feed upon the flesh of their unwilling host, who
usually dies about the time the guests are ready to pupate. One often
sees dead or dying caterpillars covered with the white cocoons of these
hymenopterous parasites. Certain larger wasps, too, use caterpillars as
food for their young. These insects paralyze their prey by stinging it,
lay their eggs on the helpless body, and seal it up in a hollow reed,
or in a nest of mud. When the wasp larva hatches it finds plenty of
living food at hand.

Chrysalids also are eaten by birds and by various carnivorous insects,
and are frequently killed by parasitic wasps and flies. Many an amateur
butterfly-hunter has been puzzled to see that some of his chrysalids
produce, not beautiful butterflies, but a lot of insignificant little
wasps.

Adult butterflies are not much troubled by parasitic insects, but they
are eaten by many birds, particularly those of the fly-catcher type, by
lizards, and by the larger dragonflies. Spiders kill a few, the great
gray robber-flies carry off a butterfly now and then, and frogs and
toads take them whenever possible. They are not much attacked by the
mammals, but I have seen a chipmunk devour a large _Papilio turnus_
with every symptom of satisfaction.

Long ages of struggle with these enemies have developed certain
protective devices--not through any supernatural intervention or any
conscious activity on the part of the butterflies, but simply by
the mechanical process called natural selection. There is a certain
degree of variation among all animals, and some of these variations
are transmitted to succeeding generations. Now, if certain butterflies
happen to vary in such a way that they are protected against their
enemies, they survive at the expense of their less fortunate fellows,
and such of their offspring as inherit the protective variation also
survive, until at last, by a gradual process of elimination, the entire
species is protected.


PROTECTIVE COLORATION

One of the commonest of the protective devices is called _protective
coloration_. It may be noted that many caterpillars are green, a color
which blends well with that of the leaves upon which they feed, and
so protects them in a measure from the prying eyes of their enemies.
Such chrysalids as are attached to green leaves or twigs are often
green also, but most caterpillars leave the foliage to pupate, and the
chrysalids are neutral gray or brown so as to be inconspicuous against
a background of bark or dead wood. Many butterflies pass the winter in
the chrysalis state, and these cold weather chrysalids are never green,
but usually some dull color which harmonizes with the winter landscape.

Another thing to be noted, particularly in caterpillars, is the
operation of the so-called _law of counter-shading_, which means simply
that the part of the body which gets the most light is usually darkest
in color. Some caterpillars habitually feed with their feet downward,
and their backs are darker than their bellies; others are accustomed to
feed in the opposite position, and the shading tones are reversed. One
has only to look at a few living specimens in their native haunts to
see the value of this arrangement.

In adult butterflies it may be observed that it is the upper side of
the wings which shows the bright colors, while the lower side is much
less conspicuous. The flying butterfly is not in much danger anyway,
and a display of color can do no great damage, but it might be fatal
to the same insect at rest. At rest, however, the wings are usually
brought together vertically, so that the highly colored upper side is
quite concealed, and only the dull under surface exposed to view. In
some butterflies--_Vanessa antiopa_, for example--the lower surface so
nearly resembles the bark upon which the insect is accustomed to rest
that it can hardly be distinguished, even when one knows exactly where
to look for it.

Some of these protected butterflies illustrate a minor protective
phenomenon known as _dazzling_ or _eclipsing coloration_. Many
observers believe that the sudden change from the bright colors of the
flying butterfly to the neutral tints of the same specimen at rest is
more confusing to a pursuer than the total absence of brilliant colors.
This dazzling and eclipsing effect is particularly noticeable in
various species of _Grapta_ and _Vanessa_.

Another thing to be remarked is the fact that many butterflies
protectively colored, such as those mentioned above, usually alight
on some object similar in color to the lower side of their own wings.
These butterflies are accustomed to rest upon the trunks of trees, and
almost invariably select one with dark-colored bark, avoiding green or
light-colored trees such as birches and sycamores. It is not claimed
the individual butterfly, after examining the colors of its wings,
casts about for a perch to match, but it is quite conceivable that
those which were attracted to light-colored bark have been gradually
weeded out of the species.


OFFENSIVE ODORS AND TASTES

Besides the method of protective coloration, some caterpillars are
protected against birds by sharp spines or hairs; others by peculiar
markings and attitudes said to approximate the appearance of serpents
or other dangerous objects. Many butterflies, it has been observed,
are protected by still other methods. The common Monarch (_Anosia
plexippus_), the Zebra butterfly (_Heliconius charitonius_), and the
Red Silverwing (_Dione vanillae_) are very conspicuous butterflies, yet
they flutter leisurely about unmolested by birds and other enemies.
This protection is due to what Alfred Russell Wallace called “a strong,
pungent, semi-aromatic odor, which seems to pervade all the juices of
their system.”

It has long been known that certain butterflies produced disagreeable
odors, but Fritz Müller, working in Brazil as early as 1876, was the
first to give the matter any very serious attention. Since Müller’s
time extensive studies have been made by Colonel Longstaff and Dr.
Dixey, two English entomologists, but very little has been done
in North America. It is certainly true, however, that the three
butterflies mentioned above (and doubtless many others) are possessed
of some taste or odor offensive to their enemies.

_Dione vanillae_ is more abundant in South America than in the United
States, and was one of the species investigated by Müller, who writes:
“The males ... when seized, open wide the anal valvulae, from the inner
side of which there appear two glands yielding a strong and nauseous
smell. The females, on the contrary, emit a similar smell from a
yellow gland extruded on the dorsum between the last and penultimate
segments.” Longstaff, who studied this butterfly in Jamaica, describes
it as “a beautiful but ill-smelling Fritillary” and says it smells like
cow-dung.


WARNING COLORATION

It has been noticed that many dangerous and distasteful insects are
rendered conspicuous by their brilliant colors, and examples of this
so-called _warning coloration_ are not lacking among the butterflies.
The Swallowtail caterpillars, which produce a very disagreeable odor,
are usually marked by two great staring eye-spots on the back of the
thorax. Some of the protected butterflies, such as the ill-smelling
Zebra and Red Silverwing, are extraordinarily conspicuous by reason
of striking color-combinations. Many entomologists believe that these
peculiar color-schemes have been developed by protected butterflies
as an advertisement of their inedible character. This view is not
as popular as it used to be, but there may be something in it; it
certainly seems to explain the structure and habits of some of the
higher animals--the rattlesnake for example--better than any other
hypothesis yet advanced.


PROTECTIVE MIMICRY

There seems to be a tendency among certain insects which are edible
and unprotected, to bear a superficial resemblance to inedible or
distasteful species. Thus certain harmless flies have developed a
remarkable likeness to wasps and bumblebees, although in structure and
habits they are really very different. Several diurnal moths, too,
have transparent wings, and yellow bands about the body which give
them the appearance of gigantic and singularly ferocious hornets. It
is certainly a great advantage for a harmless insect to resemble some
dangerous and inedible species, and the whole phenomenon of resemblance
has been called _protective mimicry_.

The best example of mimicry in American butterflies is the case of the
Monarch (_Anosia plexippus_) and the Viceroy (_Basilarchia disippus_).
The Monarch belongs to the subfamily _Euploeinae_, all the members of
which are provided with secretions which render them distasteful to
birds and predaceous insects. The Monarch advertises its inedibility by
its bright brown and black wings, and its leisurely manner of flight.
The Viceroy belongs to an altogether different group, the members of
which are readily eaten by birds, and which do not resemble the Monarch
either in form, coloration, or manner of flight. The Viceroy, however,
has gradually developed so remarkable a resemblance to the Monarch that
it is difficult to distinguish them at a little distance, although the
Viceroy is much the smaller of the two, and has a traverse black band
on the hind wing that is lacking in the Monarch. There is no doubt that
the Viceroy benefits by this resemblance, as birds (doubtless mistaking
it for the inedible Monarch) appear to give it a wide berth.

This novel situation is supposed to have come about as follows: In
the remote past the Viceroy was a blue-and-black butterfly like its
relatives, but because of the abiding principle of variation the
individuals of the species were not exactly alike--some specimens were
lighter than others. For some reason or other these lighter-colored
butterflies had a slight advantage in the struggle for existence, and
so in time the entire species was of this type, the darker specimens
having been exterminated. Finally, some individuals chanced to bear
a slight resemblance to distasteful butterflies of the Monarch type,
so that birds avoided them, but continued to feed upon their less
fortunate relatives. Thus, through a long process of natural selection,
the Viceroy has come to resemble the Monarch.


HELIOTROPISM AND LIST

It was long ago observed that plants respond definitely and
mechanically to the direction of rays of light; the leaves and flowers
of many plants always turn toward the sun and even follow its daily
course, so that the flower which turned to the East in the morning
faces due West at sunset. Similar phenomena are now known to occur
in animals. Among butterflies a good example is that of the Mourning
Cloak (_Vanessa antiopa_). This butterfly, when it alights in the
sunlight, almost invariably turns about until its body lies parallel
with the rays of light and its head points directly away from the sun.
This phenomenon is known as _negative heliotropism_, and a number of
plausible explanations of it have been advanced. Probably it is merely
another method of blending with the background, akin to protective
coloration. When the Mourning Cloak alights upon the ground, or upon a
log, it closes its wings and becomes well-nigh indistinguishable from
its surroundings, because the under side of the wings is protectively
colored. Now, if the body lies at right angles to the sun’s rays, the
wings cast a large shadow, much more conspicuous than the butterfly
itself, and hence attracting unfriendly eyes to the butterfly. If
however the body is in line with the rays of light, and the wings
brought together vertically, the shadow is insignificant. One has
only to pin a few dead butterflies on a smooth neutral background in
full sunlight to see the force of this theory. It is very probable,
then, that _negative heliotropism_ is simply a method of reducing the
too-conspicuous shadow to its lowest terms.

Other butterflies reduce the shadow by what is known as _list_, leaning
far over to one side like a sail-boat in a storm--hence the name.
The best American example of _list_ is found in the behavior of the
Wood-nymph butterfly (_Satyrus alope_), which is often seen to topple
over to one side, presenting the entire wing surface to the source of
light, lowering the top-line and thus reducing the shadow.


FEIGNING DEATH

Many insects, particularly beetles, frequently escape their enemies
by feigning death. Whether this behavior is an instinctive ruse or
a genuine paralysis induced by something akin to fright we do not
know, but it is doubtless of considerable value to the insect. Some
butterflies have been known to play possum when in a tight place.
_Vanessa cardui_, known as the Painted Lady, sometimes closes its
wings, folds its legs close to the body, and falls motionless to the
ground. Usually it is lost in the weeds or grasses, but even if found
and picked up it often allows itself to be handled without any sign
of life. Similar behavior has been reported in _Satyrus alope_, the
Wood-nymph butterfly.

Transcriber’s Notes

In the Table of Contents, the page number for Chapter VI. has been
corrected from 34 to 38.

Page 11: Changed “Fritz Muller” to “Fritz Müller”.

Page 16: In the illustration caption for Fig. I, “9. rectum, 10” was
replaced with “9. rectum; 10”.

Page 17: Changed “slender Malphighian tubules” to “slender Malpighian
tubules”.

Page 24: Changed “a reddish-brown color.” to “a reddish brown color.”.

Page 25: Changed “far from the eggshell” to “far from the egg-shell”.

Page 28: Added a missing “ before “6:00 p. m.”.

Page 34 & 38: Changed “Hesperidae” to “Hesperiidae”.

Page 48: Changed “ajax). a typical representative” to “ajax), a typical
representative”. Changed “A egg” to “A, egg”.

Page 58: Changed “green or light colored trees” to “green or
light-colored trees”.

Page 64: Changed “Wood-nymph butterfly,” to “Wood-nymph butterfly.”