PHALACRID^: 45 



Olibrus Erichs. 



This is the largest genus of the family and, unlike Stilbus, the 

 species are probably not quite so numerous in America as in 

 Europe, where some forty-eight recognized species and subspecies 

 have been made known. The American species are even more 

 monotonous in general structure and sculpture than those of 

 Phalacrus, in fact the very small and slightly elongate punctures of 

 the elytra offer so little variety, that I have been able to make but 

 little use of them systematically. Similarly, the antennae display 

 but few points of difference among the numerous forms, so that 

 within the primary subdivisions made below, reliance has to be 

 placed chiefly upon peculiarities of habitus residing in outline, size 

 and coloration, to a large extent. The striation of the elytra not 

 the impressed lines occasionally seen but the true incised striae are 

 not generically constant as they are in Phalacrus, but vary in a 

 peculiar manner. Generally there are two discal striae situated in 

 the sutural region, which, as usual in the family, never attain the 

 base, but in one important group inhabiting the southern Sonoran 

 region, there is but a single stria, and in some species there may be 

 one or two additional abbreviated and feebler true striae behind the 

 middle for a short distance and outside of the two regular striae. 

 This is an adventitious feature in vittatus, where a single short supple- 

 mentary stria is visible in about a third of the examples at hand. 

 In the types of collucens and sternalis, there are two additional short 

 striae on each elytron. The species in my collection are as follows: 



Elytra each with two subsutural striae 2 



Elytra each with a single stria near the suture 17 



2 Species occurring from the base of the Rocky Mountains eastward to 



the Atlantic 3 



Species of the Rocky Mountain system and westward to the Sierras and 



the coast regions at San Diego 10 



Species of the true Pacific coast fauna 16 



3 Elytra dark in color, each with a broad testaceous nubilous vitta 

 just outside of the median line, this paler color sometimes invading 

 the entire disk. Body elongate-oval, polished, the entire under 

 surface and legs pale ochreo-testaceous; head and pronotum piceous- 

 brown, the former of moderate size and with sparse but very distinct 

 punctures; prothorax about a third the length of the elytra, more than 

 twice as wide as long, minutely and remotely punctate, the basal 

 bead distinct, obsolete laterally as usual; elytra distinctly longer than 

 wide, rather evenly parabolic, becoming more parallel basally, the 

 punctures of the series very fine, the surface everywhere polished, 



