Who would think that these bright wings, which are so crisp and stiff that they never bend or wrinkle even by a single fold, were once like little flat buds, inside a crawling caterpillar, or bound up in the tight, horny pupa case? Let us follow the journey of these little greenish eggs, stuck on the under side of a carrot leaf. Let us follow them up their curious way, until we see them sitting on the heart of a rose, as on a throne of gold, and then suddenly sailing off among the sunbeams! Each kind of butterfly prefers some especial plant, on which the caterpillar feeds. On this plant the eggs are laid. Some butterflies like oaks best; some cabbage; some choose plants of the carrot family for a home. The butterfly which we will now hear about is the “swallow-tail.” It is one which likes fennel and wild carrot. It lays its eggs on the under side of the leaf of one of these plants. The eggs are placed in little patches. They are of a greenish color, and nearly round. The eggs of some other butterflies are of very odd shapes. The first eggs of the swallow-tail butterfly are laid in May. In eight or ten days the eggs turn nearly black. Then out comes the little caterpillar. The first thing he does is to turn around and eat up his shell! Next he begins to eat carrot leaf. He grows, and in a few days casts his skin. The caterpillar keeps on growing. To get more room he sheds his skin. He eats the cast-off skin each time. He is a very pretty caterpillar. His color is bright green. On each of his twelve rings he has a black band. On each black band there are gay, yellow spots. He is about an inch and a half long when full grown. There is a queer thing about this caterpillar. If you touch him, while he eats, he runs out a little forked horn from behind his head. He seems to want to frighten you! When you let him alone he draws in his horns. These horns can emit a strong smell. His feet are made with rings and hairs, so that he can creep safely along the plants where he feeds. His mouth is weak, so he can eat only soft leaves. In about two weeks he has eaten all that he needs. Then he creeps up a plant stem and spins a strong silk rope. He binds this rope about his body and the plant stem. That ties him fast. The caterpillars of several kinds, which tie themselves in this way for the pupa state, are called girdle caterpillars, or belted caterpillars. He is also held fast by the tail as well as by this body belt. When he is tied, his body shortens and thickens. His caterpillar skin bursts, and drops off. He is now a pupa. The pupa skin hardens into a little case. Now he neither moves nor eats. How long is he a pupa? That depends upon the time of year. In spring, two weeks are enough for the change. In hot summer, nine days or a week will do. If it is cold autumn weather, the pupa will not change to a full-grown insect until the next spring.