284 LEPIDOPTERA. 



characters for distinguishing them. The clypeus is large, the 

 antennae are inserted higher up than in otlier moths, so that 

 when 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 larvfe are thick, usually more hair}^ 

 than other moths, or, as in the typical forms, Attacus, etc., are 

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

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

 are thickly spinulated, so that the cocoons of the hairj^ species 

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

 larvae, of which the silk-worm is a type, spin very 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- 

 Meueville has found that the larvse 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, 

 H^'poprepia 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 pupae are very short and thick and easily recognized by 

 their plump form. "Bar mentions the occurrence in Cayenne 

 of an aquatic caterpillar, which produces a moth, resembling 

 Bomhyx pliKclima of Cramer. This larva lives at the bottom 

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

 (Bulletin Societe Entomologique de France, 1864.) 



Litlwsia and its allies (Lithosiinoe) have very narrow wings, 

 the antennae filiform, and the body slender. The larvae 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. LitJiosia argillacea Pack, 

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

 the wings and the tip of the abdomen are yellowish. 



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



