Bombycidae 365 



Eucleidae. Slug caterpillars spend the winter as larvae in the cocoon 

 and need careful protection at that stage. According to Dyar most 

 members of this family mate only on the day of emergence and fairly 

 large lots are necessary if matings are to be obtained. 



Lymantriidae. Tussock moths, Notolophus and Hemerocampa, may 

 be reared by the same technique as the Lymantrias [see p. 360] . They 

 also overwinter in the egg stage. Young larvae are extremely active and 

 especially fine screening may be needed for cages during the first few 

 days. 



Saturniidae. Hemileuca hibernates in the egg stage. Most pupae 

 need no protection during the winter, even in a dry room. A few with 

 light cocoons (Tropaea luna, Automeris) should be protected during the 

 winter [see p. 360]. To determine the sex pupae of this family I 

 prefer to make an opening in the side of the cocoon in order to note the 

 width of the antenna. The opening may be resealed with a small cover 

 glass if it is desired to keep track of the stage of development. 



The following are somewhat specialized in their food preferences: 

 Callosamia feeds on members of the family Magnoliaceae and Sassafras; 

 C. promethea is less particular and will also eat lilac, etc.; Samia Colum- 

 bia feeds by exception on Larix and Tsuga; Hemileuca feeds on oak in 

 the east and willow in the west, while Hemileuca lucina prefers Spiraea. 



Lasiocampidae. Tent caterpillars (Malacosoma) are particularly easy 

 to breed indoors, even under adverse conditions of temperature and 

 humidity and thus form excellent material for the school classroom. 

 They give no trouble even with mating. For M. americana the food 

 should be supplied in water or a growing plant should be provided. 

 When the first food grows stale or is exhausted the twig and tent should 

 be removed from the water but not discarded. New food may be put 

 beside it and discarded when stale unless it is too much involved in the 

 tent. Eggs are laid in early July and need no care during the winter, 

 though they should be exposed to the winter weather. 



Arctiidae. Most members of this family are general feeders. Eu- 

 chaetias and Ammalo are limited to the Asclepiadaceae and Apocyna- 

 ceae; Halysidota needs tree foods as a rule; Hyphantria makes a tent 

 and should be treated like Malacosoma, with apple forming a satisfactory 

 food; Utetheisa is partial to seed pods of Crotalaria. 



BUTTERFLIES 



John H. Gerould, Dartmouth College 



THE stage of development in butterflies at which experiments in 

 genetics are most conveniently begun is the adult. Any captured fe- 

 male, in species which I have bred, may be safely assumed to be already 

 fertilized, though very likely by more than one male. 



