No. 1. 



BOMBYCINE MOTHS OF NORTH AMERICA— PACKARD. 



209 



The spiracles are unusually narrow, being vertically almost linear, and orange-red, i. e., concolorous with the tuber- 

 cles at the end, and now directly behind them is the more or less distinct yellowish lateral slightly oblique stripe connecting 

 the lateral tubercles of the lower and of the upper row, and which touches each spiracle. (These were indicated, though 

 less distinctly, in stage II.) 



The beautiful pale purplish whitish band or edging on the suranal plate, and connecting the two lower lateral 

 tubercles of the ninth abdominal segment, is now very distinct; above it is edged within with a linear brownish line 

 forming a V, which does not reach the tubercles on either side, in fact, only extends about half way from the end of the 

 suranal plate to the base. The median dorsal tubercle on the eighth abdominal segment is still plainly double, and 

 larger than any of the others. 



We thus have assumed in this stage the characters of the larva in its final stage. 



The excellent differential characters separating this genus from other Attacinae are now defined, and the same will 

 apply to the larvae of the third stage of Platysamia, Callosamia, and Actios, as well as Samia (Philosamia). 



The following descriptions apply to two individuals specially observed during this stage: 



One (A) in stage II was seen to cast its skin July 5, at 11.15 to 11.30 a. m. The head was pale greenish yellow, like 

 a peach, but without the reddish pink tu.ge. (A. luna appears to permanently retain the greenish tint.) The thoracic 

 legs are greenish. All the tubercles are lemon-yellow, the short bristles on the thoracic tubercles black, those on the 

 abdominal segments turning black. The long whip-like hairs are white. The V-shaped band on the edge of the suranal 

 plate is a deep labradorite-azure. The lateral stripes are not yet very distinct. The spiracles are deep orange. 



Fig. 21. 



At 12.30 p. m. the head had turned almost chestnut-brown, and by 1 p. m. was of the normal dark chestnut-red hue. 



Before casting its skin, it spins a thin carpet of silk threads, to which it clings with its crochets while in the process 

 of exuviation. 



Another caterpillar (B) in stage II about molting was first noticed at 11.30 a. m. The head was small, about half as 

 large as in the next stage, pressed forward; the prothoracic segment above has a large yellow patch extending back to the 

 next segment. The region is about half as wide as the whole segment, being that portion situated behind the two middle 

 dorsal tubercles, and the brown membrane or neck connecting the head and the succeeding segment is tense. Now all 

 the tubercles are deep orange-red, while there are no fine white hairs arising from the thoracic tubercles, and those arising 

 from the abdominal tubercles are much shorter, nearly one-half, than in the next molt (A). It fastened its crochets 

 in the silk carpet it had spun previous to the beginning of the process of exuviation, so that the convulsive movements 

 of the head and thoracic segments may not cause it to fall over while in the act of throwing off the old skin. The head 

 is about one-third, and almost one-half, larger after molting than before. 



Now and then before the skin splits, and is cast off, the larva was observed to make a series of convulsive movements 

 of the head and thoracic region. 



It finally cast its skin between 2 and 3 o'clock p. m., and this individual looked like A when I first saw it. 



This larva also was observed resting with its head and thoracic region raised in a sphinx-like attitude, jerking its 

 head sideways when disturbed. The pale chestnut face forms, with the folded thoracic feet, a continuous patch of 

 color, of the same tint as that of the leaf buds, and the base of the leafstalks of the oak. In eating I do not see that the 

 maxillae and labium are of any service, but on the contrary seem to be in the way. Both are in lepidopterous larvae 

 rudimentary, and the labium in the main functions as a spinning organ. 

 83570°— 14 14 



