476 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



making a distinct angle with tbe side-margin. The elytra are truncate 

 at base, with rounded humeri; the sides are then parallel for two-thirds 

 the length; the dorsal punctures are on the 3d, or on the 3d, 5th, and 7th 

 interspaces. The tip of the prosternum is margined in most of the species, 

 but not margined in N. onetaUica. 



The side-margins of tbe prothorax are strongly reflexed, and the sides 

 strongly sinuate near the base; the angles are rectangular and prominent 

 in most species, but obtuse in others. 



A. Hind angles of prothorax obtuse; dorsal punctures on 3d interspace: 



Body more elongate 2. 



Body broader and flatter 3. 



2. Hind angles of prothorax almost rounded 10. suturalis. 



Hind angles of prothorax distinctly defined- ,.11. longula, n. si). 



3. Antenna? and legs black 12. obliqua. 



Antennae and legs ferruginous 13. oMusa, n. sp. 



B. Hind angles of prothorax rectangular ; dorsal j)unctures on 3d 



interspace: 



Sides of prothorax suddenly and strongly sinuate behind = 2. 



Sides of prothorax more gradually and obliquely sinuate behind ; color 



biack 14. liudsonica. 



2. An tenuse and legs black; color black 15. Sahlbergi. 



Antennae and legs ferruginous ; color piceous-black ... 1 6. nivalis. 

 Smaller, antennae and legs brown ; elytra metallic, with large 



dorsal x^nnctures 17. viridis. 



Much more elongate; elytra slightly metallic; dorsal punctures 



small 18. gregaria. 



O. Hind angles of prothorax rectangular ; elytra with two or three 

 rows of dorsal punctures : 

 More slender, elytra violet, somewhat coppery, striae fine, dorsal 



punctures on 3d and 7th interspaces - 19. Qebleri. 



Broader, elytra more strongly metallic; striae deeper, 3d, 5th, and 

 7th interspaces interrupted by larger punctures; prosternum 



not margined at tip - 20. metalUca. 



Black, antennae and legs dark brown ; elytral striae deep ; 3d and 5th 

 interspaces Interruj^ted by large punctures 21. hi/aria. 



Gkoup Y: — virescens. 



A single species, of robust form, with slight greenish- metallic lustre, 

 constitutes this group. The prothorax is broad, less narrowed behind 

 than usual, the sides not sinuate, margin widely reflexed, and basal 

 angles obtuse. The elytra are subtruncate at base ; the basal fold meets 

 the side-margin in a distinct angle ; the sides are slightly rounded, the 

 striae very fine, obliterated at the isides and tip; the dorsal punctures 

 are small ; the posterior one is on the 2d, the other three on the 3d 

 stria. Tbe prosternum is not margined at tip; the setigerous punctures 

 of the ventral segments are in a single row each side of the middle. 



22. JV". virescens occurs in Vancouver Island and Northern California. 



