AMERICAN COLEOPTERA. 225 



The head is always free or nearly so and usually constricted behind 

 into a neck. The antenna) are eleven-jointed in all except Xecrnphorus 

 in which the true second joint is connate with the base of the third. 

 The terminal four or five joints are usually thicker forming a club, 

 abrupt and compact in Sphserites, abrupt but with mobile joints in 

 Necrophorus, or elongate-oval and gradually formed in Silpha, etc. 

 Pteroloma and Apatetica have slender antennse, scarcely at all thick- 

 ened externally. The eyes are at least of moderate size and often 

 prominent, never absent. The thorax is variable. The elytra are 

 distinctly margined at the sides, sometimes widely, the inflexed portion 

 below the margin variable in width. This part is often erroneously 

 called the epipleuron, it is more properly the epipleural fold, the 

 epipleurae proper being narrow portions along the extreme edo-e of 

 the elytra. The abdomen is visible beyond the elytra in Xecro- 

 pJiorus, Sphserifes, Apatetica, and nearly all the species of Silj)ha, 

 but entirely concealed in the other genera, the number of segments 

 being six in all except Sphserites where there are but five. The 

 legs are decidedly fossorial in Necropliorus alone, in the other genera 

 rather slender. The tibiae are nearly always spiuulose externally, 

 very indistinctly however in several genera. The tibial spurs are 

 at least of moderate size. The anterior tarsi more or less dilated 

 in the male. 



This tribe contains all the large species of the family and none that 

 are very small, its distinctive characters being the open anterior and 

 the contiguous posterior coxas. The next two tribes have the first of 

 these characters but the hind coxae are separated. 



The genera here included seem quite homogeneous and form a 

 natural series except as to Sphserites, which is somewhat aberrant by 

 the abdomen and the compact autennal club. It seems however a 

 link toward the Histeride series, while Necropliorus shows decided 

 Staphylinide afiinities. 



Through Pteroloma and Li/rosoma as a further intermediate the 

 tribe connects with the Cholevini, and by Aijjrtes through Finodt/tes 

 with the Anisotomini. 



Some authors have divided the tribe still further and have instituted 

 tribes or families (Thomson), for Sphserites and Agi/rtes. I can see 

 no special advantage in such a course as the tribal distinctions must 

 then be brought almost to a generic basis. 



The following table gives in brief the important characters sepa- 

 rating the genera. 



TRANS. AMER. ENT. SOC. VIII. (29) JULY, 1880. 



