124 



a. Entire surface of body except the appendages with a dense covering 

 of fine short setae, giving it a furred appearance; abdominal seg- 

 ments 8-10 considerably narrower than the remainder of the ab- 

 domen Malacosoma Hiibner. 



aa. Entire surface of body except appendages never with a dense cover- 

 ing of setae giving it a furred appearance, either with a very 

 sparse covering, or without visible setae ; abdominal segments 8- 

 10 not noticeably narrower than the remainder of the abdomen, 

 b. Body sparsely covered with very fine short setae except at the cau- 

 dal end, where they are longer and coarser ; tenth segment broadly 

 rounded at the caudal end. 

 c. Lateral surface of abdomen on either side of the spiracles with 

 setae much thicker than on the dorsum ; dorsal surface of abdo- 

 men very coarsely punctate Lasiocampa Schrank. 



cc. Lateral surface of abdomen on either side of the spiracles never 

 with the setae more numerous than on the dorsum ; dorsal sur- 

 face of abdomen very finely punctate. . . .CosmotricJie Hiibner. 

 bb. Body without any visible covering of setae; tenth segment 

 abruptly narrowed at the caudal end, suggesting a cremaster. 



Tolype Hiibner. 

 The following species were examined : 

 Malacosoma americana Fabricius, disstria Hiibner 

 Lasiocampa quercus Linnaeus (Europe) 

 Cosmotriche potatoria Linnaeus (Europe) 

 Tolype velleda Stoll 



Family Bombycidae 



This family includes the genus Bombyx, which is domesticated in 

 various parts of the world (Fig. 107). The body is covered with 

 rather coarse short setae which are somewhat longer at the caudal 

 end of the body. The epicranial suture is never present. The ap- 

 pendages are arranged much as in Lasiocampidae. The labial palpi 

 are almost concealed, being overlaid by large ovate appendages, ap- 

 pearing to be heavily veined, which are presumably the maxillae (no 

 dissections were made of this species). The mandibles are repre- 

 sented by strongly elevated tubercles. The coxae of one pair of legs, 

 probably the mesothoracic, are adjacent on the meson caudad of the 

 maxillae. The legs are short, and both prothoracic and mesothoracic 

 pairs lie adjacent on the meson. The antennae are pectinate, broad 

 at the proximal end and rapidly narrowed, ending in a point oppo- 

 site the distal ends of the prothoracic legs. The mesothoracic wings 

 lie adjacent on the meson caudad of the mesothoracic legs. The 

 movable segments may be retracted so that only their caudal margins 

 are visible. There is no cremaster present. The pupa strongly re- 



