OF NORTH AMERICA. 81 



BOMBYCID.S:. 



AKCTiiN^a:. 



Genus SEIARCTIA. Packard. 



" Owing to the fine powdery scales that cover the body, the head 

 seems much freer from the thorax than in Arctia. The front is broader 

 throughout, more convex , where in Arctia it narrows towards the front 

 edge, and becomes flattened. Palpi porrect, large and long, tips obtuse, 

 surpassing the front by the entire length of the third joint. In Arctia 

 the palpi do not reach beyond the front. 



" Thorax moderately stout, finely scaled. Primaries long and nar- 

 row, the breadth being contained two and one-half times in the length. 

 Costa straight on the basal half, from thence more convex than in A. 

 Arge. The apex is produced more than usual, obtusely pointed. 

 Outer edge very oblique, one-half as long as the costa, and nearly 

 equals the length of the inner edge. In the neuration this genus is 

 more like that of Halesidota that Arctia, since the second and third 

 subcostals are curved very near the costa. Apical interspace much 

 larger than in Arctia, while the fifth subcostal is longer and straighter, 

 as are the three first median nervules, the third being curved more, 

 while the semi-ovate space enclosed between the first and third is 

 longer and broader towards the apex than in Arctia, where it is more 

 acute. In this respect it resembles Halesidota. Fourth median curvetl 

 slightly, arising much nearer the middle of the wing than in Arctia ; 

 and nearer also to the third median, to which it is parallel. 



" Its affinity to Halesidota is still more striking in the form of the 

 secondaries, which are much produced towards the apex. The costa is 

 much bent in the middle ; in Arctia it is not bent at all, and the long 

 outer edge is somewhat angulated. Legs large and stout, finely scaled, 

 resembling the stout finely scaled legs of Halesidota and Ecpantheria. 



" The species are pure white, with black stripes along the nervures, 

 not in the interspaces as in Arctia. 



" In the figure of Abbot's, the larvae of S. echo have the dorsal hairs 

 arranged in high broad tufts which show the transition from Arctia, in 

 the larvse of which the fascicles are of uniform length, to Halesidota 

 where the fascicles often form tufts and pencils of hairs. " 



Packard, Proc. Ent. Soc. Phil., vol. 3, p. 119. 



