NORTH AMERICAN EUCOSMINAE. 



41 



siderable of the ground color, while in alterana it is broad and en- 

 croaches upon this dark area. The genitalia of the two forms differ 

 enough in the shape, set, and curve of the harpe to forbid us keep- 

 ing them under one name. Veins 8 and 4 of hind wing are stalked 

 in both species. 



Male genitalia of type figured. 



Alar expanse. — 9-12 mm. 



Type.— C?it. No. 24790, U.S.N.M. 



Paratypes. — In National Collection, American Museum, and collec- 

 tion Barnes. 



Type locality. — Plummer Island, Maryland. 



Food plant. — Unknown. 



Described from male type and six male paratypes collected at 

 Plummer Island, Maryland, during August, 1903, by August Busck. 



22. THIODIA MARMONTANA (Kearfott). 



(Fig. 103.) 



Proteopteryx marmontana Keaefott, Can. Ent., vol. 39, 1907, p. 155. — Baenes 

 and McDuNNOTJGH, Check List Lepid. Bor. Amer., no. 7128, 1917. 



A somewhat larger species but closely resembling both crispanxi 

 Clemens and alterana Heinrich, differing from the latter in genitalia 

 and from the former in the greater diffusion of the median white 

 dorsal spot on fore wing and from both in its more ochreous-fuscous 

 ground color at extreme apex and along termen of fore wing. 



Male genitalia figured from cotype in National Collection, from 

 Prince Albert, Alberta, Canada ("19 July"). The asymmetry 

 shown in the figure is unusual and not characteristic of the species. 

 In this particular specimen the harpe happens to be deformed. The 

 right harpe shows the normal shape. 



Distribution according to specimens in National Collection, Ameri- 

 can Museum, and collection Barnes : Manitoba, Assiniboine, Alberta, 

 New Hampshire. 



Alar expanse. — 12.6-18 mm. 



Type. — In American Museum. 



Type locality. — Rounthwaite, Manitoba. 



Food plant. — Unknown. 



23. THIODIA OREGONENSIS, new species. 



(Fig. 104.) 



A rather large fuscous species with white ocelloid patch and a 

 median white dorsal patch on fore wing. Very like marmontana 

 Kearfott, except that in the apex and along termen of fore wing 

 the general dark fuscous ground color prevails and does not shade into 



