298 COLEOPTERA OF NORTH AMERICA. 



which are angulated; scntellum very large, acutely triangular, 

 mesonotum sparsely punctured, with narrow medial gtridulating 

 surface ; elytra finely densely punctured, rounded behind, sutural 

 angle not rounded, nor prominent. Pro- and niesosternum very 

 broad, the former overlapping the latter, both broadly emarginate 

 behind; side pieces of metathorax very wide, epiniera extending 

 beyond the hind coxae, which are widel}^ separated ; no scent 

 pores. First ventral segment much longer; 5th longer than the 

 4th, broadly subtruncate at tip. Legs slender, tibial spurs long, 

 tarsi broad, 1st joint of hind pair scarcely longer than the 2d. 



An anomalous group, having an evident aflSnity towards Cyl- 

 lene of the tribe Clytiui. 



Group II — Trachyderes. 



Insects of large size, and glabrous surface, having the antennae 

 compressed, much longer than the body in %, with very distinct 

 poriferous system, 11th joint either simple or appendiculate ; the 

 mandibles of Dendrobias % are very long, and have an acute 

 tooth near the tip, so as to appear emarginate, without really 

 being so. The palpi have the last joint cylindrical, and deeply 

 foveate. The scutellum is very large, acutely triangular; meso- 

 notum with narrow stridnlating plate. Elytra convex, narrowed 

 from the base, rounded at tip. Prothorax variable in form, tuber- 

 culate on the disk, and strongly armed on the sides in Dendro- 

 bias, uniformly convex in Lissonotus; prosternum perpendicu- 

 larly declivous in both, armed also with a large tubercle in front 

 of thecoxa? in Dendrobias; niesosternum elevated, perpendicular 

 in front; side pieces of metasternum tolerably wide, narrower 

 behind, with scent pores in Dendrobias, without them in Lisso- 

 notus ; ventral segments, 1st longer, others nearly equal. Legs 

 rather stout, thighs moderately clubbed, tibial spurs moderate, 

 tarsi broad, 1st joint of hind pair scarcely longer than 2d. 



The two genera are found only in the most southern part of 

 Texas, Arizona, and Lower California, and constitute two sub- 

 groups corresponding to Tracbyderides, and Lissonotides of 

 Lacordaire. 



Group III. — Stenaspes. 



We have removed from the Stenaspides of Lacordaire those 

 genera in which the mandibles are chisel-shaped, and emarginate 



