244 MEMOIRS ON THE COLEOPTERA 



The mentum tooth in Percosia is large, triangular, with the apex 

 deeply and sharply bidentate, the ligula corneous and very long, 

 tapering gradually from apex to the narrow base. The middle 

 tibiae are slightly bent at the middle in the male. The five species 

 of the American fauna may be knoM r n as follows: 



Latero-basal carina of the pronotum very oblique 2 



Latero-basal carina subparallel with the side margin and, posteriorly, 

 more remote from the angles than in the preceding section 5 



2 Eyes nearly flat, only very slightly convex. Body narrower and less 

 stout than in obesa, black throughout, the legs black; surface shining, 

 the elytra densely alutaceous or subopaque; head scarcely more 

 than half as wide as the prothorax, the strioles short; antennae slen- 

 der, almost as long as the head and prothorax, fuscous; prothorax 

 longer than usual, scarcely more than a third wider than long; apex 

 feebly sinuate, much narrower than the base; sides parallel in about 

 basal half, rounding anteriorly, rather broadly reflexed and punctu- 

 late, more narrowly at apex; basal angles right; impressions very 

 feeble; median stria broadly impressed, obsolete at apex; foveae 

 large, shallow, completely confluent and not separately distinguish- 

 able, and having many strong deep punctures extending across the 

 middle; elytra one-half longer than wide, fully a fifth wider than the 

 prothorax, parallel, with arcuate sides; striae abrupt and groove- 

 like, evidently punctured, the scutellar long; lateral series not at all 

 interrupted; intervals flat, feebly convex apically. Length (9) 

 10.5 mm.; width 4.7 mm. Colorado (Denver). Nebraska Le- 

 Conte diffinis Lee. 



Eyes not prominent, though much more convex than in the preceding; 

 prothorax shorter and much more transverse 3 



3 Body narrower and more elongate, the elytra more than one-half 

 longer than wide; pronotal foveae broadly and completely confluent. 

 Coloration and lustre nearly as in the preceding; side margins of 

 the pronotum diaphanously rufescent; legs piceous-black; head simi- 

 lar, except that the eyes are rather more convex and the ferruginous 

 antennae not so long; prothorax one-half wider than long, otherwise 

 nearly as in the preceding; transverse impressions rather distinct; 

 elytra more elongate than in any other and but very little wider 

 than the prothorax, with the sides evenly arcuate; striae moderately 

 coarse, groove-like, rather feebly punctate, the lateral ocellate se- 

 ries as in the preceding; intervals nearly flat, densely alutaceous in 

 the female, distinctly convex posteriorly. Length (9) 10.3-11.0 

 mm.; width 4.7-5.0 mm. Oregon (Clackamas Co.). . extensa n. sp. 



Body obese, the elytra generally less than one-half longer than wide; pro- 

 notal foveae never completely confluent, generally very distinctly 

 defined, isolated and less closely punctured 4 



4 Coloration nearly as in the preceding, the tarsi rufescent; head as in 

 extensa but relatively not quite so large; prothorax also nearly simi- 

 lar but even less sinuate at apex, the rounded sides becoming nearly 

 straight behind the middle and strongly reflexed and punctulate; 



