284 LEPIDOPTERA. 



characters for distingnishing them. The clj^peus is large, the 

 antennse are inserted higher up tlian in other moths, so that 

 wlien in doubt as to the position of some aberrant forms, a ref- 

 erence to these characters enables us to determine quite readily 

 as to their affinities. The larvsie are thick, usually more hairy 

 than other moths, or, as in the t3'pical forms, Attacus, etc., are 

 thick, fleshy and with seven longitudinal rows of long tubercles, 

 crowned with spines. The hairs, especially of the Arctians, 

 are thickl}^ spinulated, so that the cocoons of the hairy species 

 are very dense and made with but little silk, while the naked 

 larvjfi, of which the silk-worm is a type, spin xerj dense co- 

 coons of the finest silk. It is probable that the caterpillars are 

 usually developed in the egg soon after it is laid in autumn. 

 Dr. Burnett has noticed that the embryos of the American Tent 

 caterpillar are developed before winter sets in, and "Guerin- 

 Meneville has found that the larvae of the Japanese silk- worm 

 (Samia Yama-mai) are developed in the egg within a few days 

 of their deposition in autumn, although they are not hatched 

 until the following spring." (Zoological Record, 1864.) 



Several moths of this family (Arctia pudica, Setina aurita, 

 Hypoprepia fucosa, etc.) have been known to produce a stridu- 

 lating noise by rubbing their hind legs over a vesicular expan- 

 sion situated on the sides of the thorax, and the Death's-head 

 Sphinx has long been known to produce a creaking sound. 

 The pupce are xerj short and thick and easily recognized by 

 their plump form. " Bar mentions the occurrence in Ca3'enne 

 of an aquatic caterpillar, which produces a moth, resembling 

 Bomhyx jihredima of Cramer. This larva lives at the bottom 

 of the water, and feeds on the roots of an abundant weed." 

 (Bulletin Soeiete Entomologique de France, 1864.) 



LitJwsia and its allies (Lithosiinaj) have very narrow^ wings, 

 the anlenuic filiform, and the body slender. The larva? are 

 cylindrical and covered with short, spinulated hairs. Some of 

 them do not spin cocoons, so far as we know, the pupa of Cro- 

 cota being found under stones with the dried larva skin still 

 adhering to the tip of the abdomen. Lithosia argiUacea Pack. 

 is slate-colored, with yellow palpi and prothorax. The base of 

 the wings and the tip of the abdomen are j- ellowish. 



Lithosia casta Sanborn (Fig. 214) is an undescribed species 



