186 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 90 



the veins, black; at apical third an indistinct outwardly curved, 

 broken, white fascia formed by short series of white scales following 

 the veins; around termen a series of seven indistinct black spots; 

 cilia light smoky. Hind wing fuscous, lighter basally; cilia light 

 brownish ochreous with a distinct fuscous subbasal line. Legs 

 blackish fuscous outwardly, mixed with whitish ochreous inwardly ; 

 annulations of tarsi whitish ochreous. Abdomen gi-ayish above, 

 whitish ochreous beneath. 



Male genitalia. — Harpe broad, sparsely clothed with hairs ; cucullus 

 broadly rounded; clasper stout, sharply and outwardly angled; 

 distal end with small scobinations ; sacculus narrowly folded, with 

 spinous process from base curved toward cucullus; elements of 

 spinous basal process long, stout, rather few in number. Anellus 

 longer than broad; anterior margin deeply cleft; lateral edge con- 

 vex, undulating; posterior margin concave. Aedeagus stout, gently 

 curved, sharply pointed; base with large, winglike dorsal expansion 

 and spoon-shaped ventral process by which the aedeagus articulates 

 with the anellus. Vinculum rounded. Transtilla broad, narrowly 

 hood-shaped; lobes of transtilla mainly indicated by hairs. Socii 

 small, hairy. 



Female genitalia.. — Ostium large, oval ; genital plate broad, strongly 

 sclerotized, somewhat evaginated ventrally around ostium ; anteriorly 

 the ventral sclerites are produced to form two conspicuous, shallow, 

 sclerotized pockets equal in length to the sclerotized part of the duc- 

 tus bursae ; ductus bursae strongly sclerotized in posterior third, the 

 remainder membranous; inception of ductus seminalis just before 

 ostium; bursa copulatrix large, with a conspicuous, strongly sclero- 

 tized, toothed signum in posterior part. 



Alar expanse, 20-22 mm. 



ry;?^.— U.S.N.M. No. 52073. 



Type locality.— Ya]nmn, Yakima County, Wash. (18-V-31, Fred 

 P. Dean, collector). 



Food plant. — ^Unknown. 



Remarks. — ^Described from the 9 type, 3 $ and 3 9 paratypes as 

 follows: Walla Walla, Wash., ^ $ $ and 3 9 9 (Clarke, No. 4731- 

 4736; [8-14-VI-1931, D. H. Brannon]). 



This very distinct species cannot be confused with any other de- 

 scribed from North America. A few species {leptotaeniae, mulfi- 

 fldae, and angustati) show a slight tendency toward the formation 

 of the shallow anterior pockets of the genital plate but none has 

 them so well developed as yahimae. 



I suspect that the larva will be found on some species of Lomatiwm 

 or a closely allied plant. 



