Vance Randolph

“ 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. ”

“ 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 [Pg 20] eye, and they vary widely in shape and color as well as in size. ”

“ 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 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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 [Pg 9] sorts of handicaps, and will always be a classic to American students of the subject. ”

“ 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. ”

“ 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. ”

“ 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 [Pg 17] 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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 [Pg 52] 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 ”

“ 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 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 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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 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. ”

“ 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.” ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”