1 86 MEMOIRS ON THE COLEOPTERA 



spinulo-setose beneath, the anterior tibiae in general gradually and 

 feebly everted and acute externally at apex. The trochantin is 

 distinct and the elytra widely embrace the sides of the body, as in 

 all our genera excepting Litasida and the Microschatia section, and 

 may or may not have an acute or cariniform margin as in Euschides. 

 The prosternum between the coxae is more like that of Pelecyphorus 

 than the Euschides type, being rather gradually declivous behind 

 and extending somewhat onto the anterior part of the mesosternum. 

 The groups, some of which are subgeneric, are five in number as 

 known at present; they may be defined by the following general 

 characters : 



Elytra without a distinct costuliform side margin, except before the 

 middle or near the base; body convex and deep black throughout 

 as a rule, the surface smooth or nearly so 2 



Elytra with a distinct costiform or cariniform side margin, extending 

 nearly or quite to the apical angles, or at least far behind the middle; 

 basal angles of the prothorax acute and obliquely everted; body less 

 convex, not always deep black 3 



2 Body narrow in form, the anterior parts notably small when com- 

 pared with the hind body; basal angles of the prothorax generally 

 finely acute but only moderately prominent Group I 



Body broad and oblong-oval, much more parallel, the prothorax nearly 

 as wide as the elytra and more transverse, with the hind angles 

 obtuse, never prominent; sides of the elytra never cariniform except 

 basally Group II 



3 Elytra feebly convex, each with three lines of wrinkles, which are 

 transversely united by intervening reticulations Group III 



Elytra feebly convex to almost perfectly flat, having feeble and con- 

 fusedly rugose sculpture, which is usually resolvable into some four 

 or five faint and feebly defined approximate longitudinal lines, the 

 minute subgranuliform punctures each with an extremely short 

 inclined stiff seta Group IV 



Elytra flat, without longitudinal lines of rugosity, the fine granuliform 

 punctures bearing each a minute hair Group V 



All of these groups inhabit the southern Rocky Mountain system 

 and its easterly extensions, excepting the last, which is confined to 

 Lower California. 



Group I Type guadricollis Horn. 



At first glance it would almost seem that this group should con- 

 stitute a separate genus, the form of the body is so distinctive, but 

 on closer observation it can readily be seen that it is closely affili- 

 ated with the following polita group, and through that to opaca 



