230 COLEOPTERA OF NORTH AMERICA. 



The two species found in the Middle and Southern States are 

 dull, opaque black. The genus has been recently increased by a 

 larger (-65 inch) shining black species from Florida, P. nitidus 

 Lee, in which the large punctures of the elytra are arranged in 

 regular rows, and the intervals are not elevated. It also differs from 

 the other two species by the outer joints of the antenna? not being 

 transverse, and by the labrum being more prominent ; the latter 

 is possibly an accidental character, as I have observed in Cibdelis, 

 Eurymetopon, and other genera of various tribes, that the labrum 

 is capable of protrusion and retraction to a limited degree. 



Group II. — ITpes. 



In this group the hind coxa? vary in position ; the metasternum in 

 the apterous species is very short, but in the winged ones long ; the 

 epipleura? do not reach the tip of the elytra in most of the genera, 

 and in others they are gradually narrowed, barely reaching the tip. 



These species are found under bark of dead trees. Our genera 

 are as follows : — 



Epiplenrse not attaining the tip of the elytra ; 



Tibiee grooved on the inner face ; (metasternum short). Ccelockemis. 

 Tibia? not grooved on the inner face ; 



Mentum flat, rounded in front ; (metasternum short). Cibdelis. 



Mentum generally convex, subtrilohate or broadly emarginate ; 

 Gula sulcate transversely ; (metasternum short). Scotob^nus. 

 Gula not sulcate ; 

 Margin of front reflexed. Centronopps. 



Margin of front not refiexed ; (metasternum long) ; 

 Thighs very thick, clavate ; 

 Mentum prominent at the middle. Merinus. 



Mentum broadly emarginate. Pachyurgus. 



Thighs slender, or slightly thickened ; 

 Mentum flat, broadly emarginate in front ; hind tarsi long. 



Xylopinus. 

 Mentum slightly convex, almost truncate in front ; hind tarsi 



short. Haplandrds. 



Mentum prominent at the middle, strongly trilobed ; hind tarsi 

 long. Upis. 



Epipleurse reaching the tip of the elytra ; metasternum long ; hind tarsi 

 short ; 

 Head with a deep postocular furrow ; 



Mentum prominent at the middle. Glyptotps. 



Head not grooved behind the eyes ; 



Mentum flat, lateral lobes small, inflexed. Nyctobates. 



Mentum flat, lateral lobes wanting. Iphthimps. 



