478 AMERICAN PACHYBRACHYS (cOLEOPTERA) 



microps though rather less incrassate apically. The maculation 

 of the head and prothorax is nearly always very vague, but on 

 the elytra varies from distinctly and rather sharply defined to 

 almost entirely wanting. It consists here of a series of spots or 

 clouds extending along and interiorly adjacent to the lateral stria 

 and within these a discal series or group usually more or less 

 indefinite in outline and often suffusedly confluent. The tip of 

 the humeral umbo is almost always dark and a common sub- 

 apical sutural spot is rarely lacking. The relative dimensions of 

 the tarsal joints show a considerable amount of variation, the 

 basal joint of the front tarsi — e. g. — l)eing distinctly longer than 

 wide, the terminal joint not or but slightly longer than the basal 

 one in eastern specimens, while in some examples (not all) from 

 California and Arizona the basal joint is as wide as or even wider 

 than long, and the terminal joint is as long as the first two joints 

 combined. This disparity, however, seems gradational and I 

 have not as yet been able to base a separation on it. 



The following form or variety seems sufficiently well marked 

 to merit a name and may indeed be specifically distinct. 



Var. heteroderus new variety 



Larger than average hcpaticus, head and prothorax brown, elytra dull ochre- 

 ous, thickly brown punctate, with a dark brown stripe consisting of the fused 

 lateral spots along the submarginal stria, the submarginal interspace clear 

 ochreous and more convex; a common sutural spot. Prothorax inflated and 

 widest at or slightly in advance of the middle; very densely punctate to the 

 extreme margin, the punctures a little coarser than on the elytra. Basal joint 

 of front tarsi as wide as long, the claw joint subequal in length to the basal two 

 joints. 



Length 2.7 to 3.7 mm.; width 1.4 to 2 mm. 



Distribution. — Arizona: Peach Springs, Aug. 25, collected by Wickluim, 

 type female; Prescott (Van Dyke Coll.). 



The form of the prothorax is quite remarkable and constitutes 

 the chief distinguishing character of this form. There is a certain 

 amount of instability in prothoracic outline in the series of 

 hepaticus at hand, but nothing that approaches very closel}^ to 

 the present extreme. 



159. Pachybrachys microps n(>w species 



Black, with a few very small barely detectable obscure rufous 

 spots or shades near the margins of the j^rothorax and elytra; 

 punctuation throughout extremely dense but not very coarse, 



