212 H. C. FALL. 



Anterior coxae widely distant, the antennae received between them. 



Presternum produced behind into two long slender horn like processes; an- 

 tennas 10-jointed Dorcatoma. 



Prosternum truncato-emarginate behind ; antennae 8-, 9-, or 10-jointed. 

 Eyes minutely emarginate. 



Elytra without discal striae Eutylistus. 



Elytra with discal stria Byrrliodes. 



Eyes deeply acutely incised, the fissure extending to or beyond the middle. 



Csenocara. 

 PETALIU1M LeConte. 

 Tlie chief structural character of this genus, and one by which it 

 may be distinguished from all others, is the strongly produced 

 and broadly expanded metasternal lobe; but aside from this the 

 species possess a perfectly characteristic facies which makes them 

 easily recognizable. The form is parallel, more or less elongate, 

 rather strongly convex, with sparse or moderate recumbent pubes- 

 cence. Head deeply sunk in the prothorax, not visible from above, 

 eyes moderate in size, though larger in the male, not very convex. 

 Antenna? about one-third the length of the body, 11-jointed, the 

 first joint long and moderately thick ; second globose, as wide as the 

 first; third and fifth transversely triangular; fourth, sixth and 

 seventh much narrower and smaller, the seventh usually evidently 

 larger than the sixth; eighth smallest; ninth and tenth similar, 

 triangular, longer than wide, and each about as long as joints 3-8 

 inclusive; eleventh a little longer, oval, pointed. Joints 9-11 are 

 together as long as or somewhat longer than all the preceding. 

 Terminal joint of both maxillary and labial palpi moderately elon- 

 gate, with nearly parallel sides, the apex bidentate because of a 

 deep semi circular emargination. Prothorax as wide as the elytra, 

 sides parallel, hind angles sharply defined and nearly right, front 

 margin thickened and a little reflexed, disk at most feebly gibbous 

 at middle with shallow oblique impressions at each side. Elytra 

 punctate striate, punctures becoming smaller or nearly disappearing 

 at apex, the two outer lines more deeply impressed. Prothorax 

 strongly excavated beneath for the reception of the head ; proster- 

 num short, front coxa? widely separated, their summits forming 

 small, very narrow transverse plates, the articulation with the tro- 

 chanters posterior. Mesosternum deeply abruptly excavated longi- 

 tudinally, invisible without dissection. Metasternum large, pro- 

 duced between the middle cox?e in a broadly expanded lobe which 

 covers the mouth and anterior tarsi in repose, transversely grooved 



