304 COLEOPTERA OF NORTH AMERICA. 



very distinct scent pores near the hind end. Tibiae not carinate 

 in our species. 



This group evidently belongs to the same series as the pre- 

 ceding, with which it connects closely, though assuming a form 

 which is characteristic. The prothorax is very elongate and 

 cylindrical, as in certain Elaphidion, but the antennae are never 

 spinose. 



The two genera belonging to our fauna may be thus distin- 

 guished : — 



Front coxal cavities closed behind. Compsa. 



Front coxal cavities open behind. Heteeachthes. 



Of Compsa, two species are found in Lower California; the 

 genus is easily distinguished by the character given above, and 

 by the joints 3-6 of the antennae being distinctly carinated ; one 

 of the species G. jjuncticollis Lee, is remarkable for the dull 

 color, and coarsely punctured prothorax. 



Group IV. — Curii. 



The singular characters of the two species of Curius Newm., 

 compel me to separate them as a distinct group, which is easily 

 recognized by the coarsely granulate eyes, and very strongly 

 clavate thighs, armed beneath with a broad tooth. The form is 

 elongate, in the typical species depressed, dull, and slightly 

 pubescent ; in C. scambus cylindrical, polished, and glabrous, 

 resembling Ibidion. The front is small, declivous, the antennal 

 tubercles not prominent, the palpi somewhat unequal, the man- 

 dibles small and acute ; the antennas are slender, longer than the 

 body, annulated, finely punctulate and pubescent. The front 

 coxae are globose, prominent, nearly contiguous in G. dentatus, 

 separated in C. scambus, and the cavities are open behind ; the 

 middle coxa? are entirely inclosed by the sterna, and the side 

 pieces of the mesothorax are undivided;* the first joint of the 

 abdomen is as long as the two following in C. dentatus, but 

 equal to the three following in C. scambus. 



The differences above noted indicate the necessity of separating 

 G. scambus as a distinct genus for which the name Plectromerus 

 \.Dej. may be adopted. 



* This character is otherwise only known to me in the tribe Ancylo- 

 cerini, also a very anomalous form. 





