216 



THE CECROPIA AND PROMETHEA MOTHS. 



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 lead- 

 ing 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 de- 

 veloped, it is surprising how little this 

 side of Zoology. has been encouraged by 

 many of our better colleges and universi- 

 ties. 



From the standpoint of the teacher, in- 

 sects as a rule, stand very high with re- 

 gard 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 re- 

 membered 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 at- 

 tracted 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 ditiicult to distinguish them. The fe- 

 males 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 larg.e 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, pale in 

 color, and are 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 differ- 

 ent 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 

 largetubercles. Thoseabove 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 re- 

 lated 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 are preyed upon, and the larva 

 dies. A wasp-like insect which preys up- 

 on 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 



