162 Journal Nevv York Ent. Soc. [Vol. ii. 



C. populi Walker. 



1856 — Cossiis populi \s MJVJe.^, Cat. Brit. Mus., pt. VII, p. 1515. 

 1882 — Cossiis tutgvfzi Bailey, Papilio, Vol. II, p. 93. 



Collar and head yellowish gray, thorax partly black. Fore 

 wings with nearly white ground shaded with blackish, with black 

 and reticulated lines, those crossing the center of the wings most 

 distinct. Hind wings yellowish gray, mottled with blackish out- 

 wardly. Expanse, 60 — 80 mm. 



Habitat^ Nevada, Hudsons Bay. 



C. ore Strecker. 



1S93 — Ccj-JWJ tvr Stkecker, Proc. Acad. Nat. Sci. Phil., p. 282. 



Closely similar to C. populi hwX. the lines more reticulated, less 

 strigose, giving the fore wing a mottled appearance. Otherwise 

 the species are alike. Expanse, 55 — 75 mm. 



Habitat, The Pacific northwest. 



C, perplexus Neumxgen &^ Dyar. 



\'i)C)i—Tr}paiiuspe)plexus Neumcegen & Dyar, Journ. N. Y. Ent. Soc, 



Vol. I, p. 31. 

 Ash gray ; reticulations becoming obsolete, irregular and 

 branched; median and sub-terminal lines remain. Secondaries 

 unicolorous, pale cinereous, sub-translucent. Expanse, n mm. 

 Habitat, Colorado. 



C. mucidus Hy. Edwards. 



18S2 — Cossiis mucidus Hy. Edwards, Papilio, Vol. II. p. 126. 



Reticulations converted into dense transverse striga?, the 

 fore wings all obscured by blackish shading except the basal costal 

 half where ground color appears, sordid white. Secondaries sordid 

 white, minutely strigose, appearing pulverulent. Expanse, 36 — 

 40 mm. 



Habitat, Arizona. 



Genus Prionoxystus Grote. 



1882 — Prionoxystus Grote, Nevv Check-list, p. 63. 



1874 — \Xystus Grote, Proc. Amer. Phil. Soc, Vol. XIV, p. 262. 



Synopsis of species. 

 Wings opvqque, secondaries of cT partly orange .... robiniae. 



Secondaties of 9 a'so orange tinted var. quercus. 



Wings sub-hyar.ine, no orange maciTlurtrei. 





