466 SYNOPTIC COLLECTION. 



The mesothorax bears a pair of shoulder lappets or 

 patagia which protect the basal portion of the front wings. 

 Kellogg 1 has pointed out that these organs are small and 

 inconspicuous in the generalized moths but are remark- 

 ably developed in these swift-flying Sphingidae. 



The Bombycidae are well known through the silk made 

 by Bombyx mori Linn. Its cocoon (No. 1183) yields 

 the greater part of the silk of commerce. This moth (No. 

 1184) has been domesticated since early times and in con- 

 sequence has almost wholly lost the power of flight. The 

 wings (PI. 1185, fig. i, fore wing; fig. 2, hind wing) of 

 the Bombycidae are interesting, since the frenulum is in 

 a vestigial condition, as seen in Bombyx mori Linn. (fig. 

 2,/), while the humeral angle of the wing (fig. 2, //) is 

 becoming extended as in the group of frenulum losers 

 soon to be described. 



Dr. A. S. Packard has pointed out in his valuable 

 memoir on Bombycine moths 2 that the larvae of the more 

 generalized moths, the Noctuidae, for example, are low- 

 feeders ; that is, they live on grasses and low-growing 

 plants, and that as a rule they are without spines, horns, 

 tufts, or other ornamentation ; their color is green or 

 some quiet shade. On the other hand, the larvae of the 

 more specialized moths, like the Bombyces, have taken 

 to tall blossoming plants or to trees. They have become 

 adapted to their environment by developing brilliant 

 colors or varied ornamentation. 



The resemblance often existing between a caterpillar 

 and its surroundings is illustrated by Nerice bidentata 

 Walk. (PL 1186). The saw like back of this larva and 

 its green color dashed with white are in harmony with the 

 serrated margin and color markings of the elm leaves 

 upon which it feeds. 



One species of the genus Heterocampa, (//". obliqua 



iAmer. Nat., XXIX, March, 1895, p. 255. 



2 Mem. Nat. Acad. Sci., VII, Monograph i, 1895. 



