74 CASEY 



two-fifths, the reflexed humeral part of the epipleurae narrow and 

 scarcely visible from above, not at all prominent ; surface with 

 the longitudinal lines obsolete basally, becoming gradually distinct 

 posteriorly, opaque, the shallow opaque anastomosing foveae very 

 indistinct basally, becoming larger and more evidently defined 

 apically; flanks rather gradually inflexed, the under side less 

 opaque but scarcely punctured ; epipleurae nearly as in the pre- 

 ceding species; anterior tibia? only very moderately produced 

 externally at tip, very feebly sinuate externally; under surface 

 more shining, alutaceous. Length 8.4 mm. ; width 5 8 mm. 

 Kansas (Fort Dodge), Warren Knaus peropacus n. sp. 



Body similarly small in size but much narrower and more gradually 

 and acutely produced behind than in any other species, deep black, 

 opaque ; head flat, finely, sparsely punctulate, broadly sinuate at 

 apex, the sutures very fine ; prothorax nearly as in peropactis but 

 much less transverse and less explanate at the sides, being only 

 feebly declivo-explanate even posteriorly, the marginal bead much 

 finer and feebler; elytra fully a fifth longer than wide, at base 

 equal in width to the prothorax, the sides thence parallel nearly 

 to the middle, then gradually arcuate and converging to the 

 acutely rounded and prominent apex ; surface convex, with distinct 

 and close-set though feeble ridges which are wholly lost on the 

 flanks and toward apex, the intervals with very indistinct and 

 shallow anastomosing foveae, which are still more opaque than the 

 ridges; under surface rather shining though evidently alutaceous, 

 the prosternal process flat, evenly, circularly rounded at tip; basal 

 joint of the hind tarsi a little longer than in peropacus and about 

 as long as the entire remainder. Length 9.0 mm. ; width 5.4 

 mm. (c?)* Kansas (Logan Co.), Warren Knaus... acutus n. sp. 



There are three evident groups of species in this genus, com- 

 posed, first, of small forms allied to dubius, forming the Compi- 

 nus group, inhabiting southern California ; second, the productus 

 group, including two distinct divisions represented by -productus 

 and dijficiliS) depending upon bodily form and character of the 

 elytral sculpture, very satisfactorily connected by composilus, 

 which has the parallel form, very coarse elytral punctures and 

 rugose surface of difficilis and the longitudinal impunctate lines 

 and considerable sexual divergence characterizing -productus, 

 explanatus and vicinus; this second group of the genus also 

 peculiar to the California fauna and extending only slightly into 

 Arizona ; thirdly, the last eight species of the table form a dis- 

 tinct group inhabiting the southern Rocky Mountain region, 

 extending into Mexico but never occurring in California. Se- 

 culus,politus and coquilletti are unknown to me, but it is inferred 



