238 MEMOIRS ON THE COLEOPTERA 



acute, the scutellar extremely short, sometimes obsolete; intervals 

 flat or nearly so, the discal puncture strong, at four-sevenths, the 

 lateral line of foveae medially interrupted; hind tarsi short, not 

 three-fifths as long as the tibiae, the first joint not quite as long as 

 the next two combined; anterior tarsi (cf) feebly dilated and 

 biseriately squamulose beneath, the middle tarsi slender and un- 

 modified. Length (d 71 9 ) 4.7-5.2 mm.; width 1.7-2.0 mm. Cali- 

 fornia (Lake Tahoe and in Siskiyou Co.). [Harpalus nigrinus Dej. 

 Alaska; Geobcenus quadricollis Lee. Lake Superior; Trechus tibialis 

 Kirby] nigrinus Dej. 



This species seems to be very widely disseminated through the 

 colder parts of North America but is not very abundant. 



Triliarthrus n. gen. 



Except in the oblique linear form of the frontal foveae and in a 

 certain difference of habitus, due to the arcuate or anteriorly swollen 

 sides of the prothorax, there is very little difference between this 

 genus and the preceding. The ligula and paraglossae, mental 

 emargination and tooth, are all nearly similar; the labial palpi 

 are slender, the second and third joints exactly equal in length. 

 The first three joints of the antennae are glabrous, the third with 

 merely a single corona of long setae at apex and the scutellar stria 

 is generally very short, sometimes almost obsolete and most distinct 

 in kirbyi. The anterior male tarsi, are distinctly dilated and have 

 beneath a double row of very large horizontal, thin and hyaline 

 plates, which are transversely plicate but not divided, the middle 

 tarsi slender, not at all or but feebly dilated, though usually having 

 a double series of small slender squamae; the hind tarsi are slender, 

 with the basal joint not quite as long as the next two combined and 

 generally not as long as the fifth. The species are moderately 

 numerous as follows: 



Species of the Atlantic regions; basal angles of the prothorax variable. .2 

 Species of the true Pacific coast fauna; basal angles always sharply 



defined 5 



2 Basal angles of the prothorax obtuse and obviously rounded 3 



Basal angles obtuse but sharply defined and generally minutely promi- 

 nent 4 



3 Body elongate-suboval, convex, shining, black, the edges of the pro- 

 notum finely, diaphanously pale, the elytra testaceous, sometimes 

 obscure, with a large feeble and very indefinite darker cloud, the 

 base before the carina deep black; under surface black, the legs and 

 epipleura obscure rufous; head moderate, with rather prominent 



