In the study of Natural History it is the habits and life histories of the living animals which appeal most strongly to young people. A large part of the leading Botanists and Zoologists of this country began, as young people, their studies of Nature by collecting animals and plants and studying their life history and habits. It is this dynamical side, the relation of the animal to its surroundings, which arouses our interest. Since this has been the most natural method by which the interest in nature has, been developed, it is surprising how little this side of Zoology has been encouraged by many of our better colleges and universities.

From the standpoint of the teacher, insects as a rule, stand very high with regard to the interest which they arouse in scholars for nature study. This is natural, since the great abundance and interesting habits of these animals make them comparatively easy to study.

The two insects which we figure this month are very common and widely distributed, and thus have become very generally known. When we once become familiar with them, these beautiful moths are of perennial interest, and each season one is pleased to renew his acquaintance with them.

The Cecropia is our largest and to many persons the best-known moth. Its gigantic size, varying from about 4 to 7, inches in expanse of wings, together with its bright colors, makes it an easily remembered insect. The scientific name of this moth (Samia cecropia) is the first scientific name of an insect that many of us can recall learning. The time of active flight is at night, and thus it is that they are so frequently found in numbers about electric lights to which they have been attracted by the intense light. Their rather awkward flight and large size often lead to their being mistaken for bats.

The differences between the sexes are not so manifest as in Promethea, yet it is not difficult to distinguish them. The females are larger and have stouter bodies, but the most conspicuous difference is that the "feelers" or antennae of the mate are feather-like and very large and broad, while those of the female are only about one-half as broad.

The eggs are somewhat flattened, about one-tenth of an inch long, pate in color, and arc deposited by the female in small patches upon a large variety of plants, since there are about fifty of these upon which the larvae will feed. The eggs usually hatch in about a week or ten days, the young larvae being very different in appearance from the mature ones. The changes in appearance are brought about by five moults or sheddings of the skin. The full grown larva is pale green or light blue, 3 or 4 inches long, armed with eight more or less complete rows of large tubercles. Those above on the second or third thoracic segment, are bright red; all the others are yellow except those on the sides of the body and on the first thoracic and last body segment, which are blue. Unfortunately, these colors soon fade in the dead larva as is seen in the plate. This wonderful development of tubercles seems to be in some way related to the arboreal habits of the larvae.

Although a variety of parasites which prey upon these larvae is not large, they are very numerous in individuals, and it is to this cause that only a small per cent of the larvae ever produce moths. These parasites develop beneath the skin of the larva as footless grubs, which, at first, do not attack the vital organs, but later these organs art preyed upon, and the larva dies. A wasp-like insect which preys upon this larva well illustrates in its habits the crudeness of many instincts. The female will lay eight or ten eggs upon one caterpillar, but as the young parasitic grubs require a large amount of food, only one is able to mature and the others perish.

The insect parasites seem, in many cases, to mature and transform into the adult stage after the caterpillar has built its cocoon, and thus many parasites lose their lives, since they are not always able to escape from the cocoon. A cocoon will sometimes be found filled with these small insects, which have not been able to make their escape, and have thus died in prison.

The adult larva, unlike Promethea, usually spins its cocoon not attached to a leaf, but along a stem; sometimes, however, they may be placed in other situations.

In about two weeks after the cocoon has been spun, the larva transforms into a chrysalis, in which stage it hibernates during the winter, and from which it emerges, in May or June.