1873.] 





[Horn. 



fication" of Dr. Leconte. Bamnius has been removed from the first 

 and placed near Acritus in the second, the reasons for -which will be given 

 in the i^roper place. Trihalus has the prosternal lobe short, but its lat- 

 eral prolongations form the lower boundary of the antenual fossa, a 

 structure which cannot exist in the second sub-tribe. 



Sub-Tribe Histrini. 



- This snb-tribe contains in our fauna the larger number' of genera and 

 species. 



The genera are thus distinguished : 

 Antenual cavities at the anterior angle of the thorax, 

 usually closed beneath more or less entirely by the 

 pectoral plate, but open in front. 

 Antennal club more or less oval, pubescent, and 

 usually, distinctly annulated. 

 Mandibles moderately jn-ominent, upper edge round- 

 ed, not clasping the epistoma, labrum trape- 

 zoidal. 

 Antennal club broadly oval, distinctly annulated, 



elytra never acutely margined HiSTER. 



Antennal club elongate oval, aj^parently solid but 



pubescent, elytra acutely margined Tkibalister. 



Mandibles retracted, upper edge acute, at base clasp- 

 ing the epistoma, labrum short, very transverse. 

 Presternum broad, lobs short, elytra scarcely 



striate, form ovate Tiubalus. 



Prosternum moderate, lobe moderately prolonged, 



elytra striate, form oblong Epiervs. 



Antenual club obconical, solid, glabrous. 



Prosternal lobe thick, horizontal. Epistoma trun- 

 cate, labrum normal Het.erius, 



Prosternal lobs thin, broad, detiexed. Epistoma 



bifurcate, labrum small Echinodes. 



Antennal cavities slightly behind the anterior angles, 

 open beneath, closed in front by the thickening of 

 the inflexed portion of prothorax. 



Antennae frontal ' 0:js xnopmLus. 



Antennal cavities at the middle of the thorax beneatli, in 



front of the outer portion of the coxfe, prosternal 



plate not prolonged laterally. 



Anterior tibiai with moderately large terminal spur. . . 



Anterior tibije dilated, middle and hind tibiae 



slender PAROMALtis. 



Tibia) all dilated Dexdrophilus. 



Anterior tibiae with small terminal spur. Anterior 

 tibia) slightly dilated, middle and hind tibiie slen- 

 der AXAPLEUS. 



