“Still others have an even more repulsive look, bristling as they do with clusters of prickles and with tufts of long hair. From these ugly creatures, whose very touch would be so disagreeable to us and would make us utter cries of fear, come some of the most beautiful butterflies of our part of the world. Such is the caterpillar that browses the leaves of the nettle and becomes the Vanessa Io or peacock-butterfly. It is black with white spots, and wears a rough armor of toothed prickles. The butterfly, the Vanessa, has wings of a bright brick-red adorned with a large eye of mingled black, violet, and blue. Who would ever imagine, unless he had seen the transformation or heard about it, that so ravishing a creature has such an origin? “But for all their hairs and prickles caterpillars need cause us no alarm. Nothing about them justifies the fear they too often inspire. No caterpillar is poisonous, no caterpillar seriously injures the hands that touch it. Yet it is well not to repose full confidence in hairy caterpillars: sometimes the hairs become detached and cling to the fingers, causing rather lively itching sensations. But a little scratching ordinarily ends the trouble. Accordingly any one who should hereafter be afraid of caterpillars would not deserve the privilege of chasing butterflies. “Every larva is a gluttonous eater, because it must grow big and accumulate the wherewithal for its subsequent changes of form. Nor are caterpillars lacking in response to this serious duty. The future butterfly’s welfare is at stake. Made solely for eating, the larvæ gnaw and browse unceasingly. Each one has its own particular kind of sustenance, its chosen plant, and nothing else meets the requirements. The larva of the Vanessa selects the nettle and turns with aversion from all substitutes; that of the Pieris, a white butterfly with black spots, will have only the cabbage; that of the Machaon, a butterfly with large wings that end in a sort of tail, feasts on fennel; and so of others. “After attaining the full size assigned to them by nature, caterpillars, like other larvæ, prepare for their transformation. Some shut themselves up in a cocoon made from a silken thread that they spin from their mouth, while others content themselves with binding together, by means of the small supply of thread at their disposal, particles of earth, bits of wood, and hairs plucked from their own body. Thus is obtained, at small expense, a sufficiently substantial temporary abode. Finally, still others, especially among the butterflies that fly in the daytime, merely seek a retreat on the side of some wall or against a tree-trunk, and there suspend themselves in a girdle of silk.