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 quite 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 male are feather-like and very large and broad, while those of the female are only about one-half as broad.