122 AMERICAN COLEOPTERA 



the genus, have added no other distinguishing characters, and it 

 apparently did not find favor with LeConte, who at least did not 

 accept the name in a generic sense. 



The mere presence or absence of pronotal costae carries in itself 

 very little weight, and without concurrent features of structure or 

 fades can be considered no more than a convenient means of subdi- 

 vision. Moreover, a careful comparison will show that there is no 

 great difference in this respect between certain species of Lathridius 

 in which the costse are more feebly developed and tend to become 

 obsolete anteriorly, and others of Enicmus, in which the margins of 

 the median sulcus become distinctly carinate or subcarinate poste- 

 riorly where they cross the transverse impression. As we have 

 already seen, however, the prosternal characters of Lathridius are 

 precisely those upon which LeConte founded Step hostet hus and dis- 

 tinguish it sharply from Enicmus, in which the prosternal process 

 reaches the hind margin, completely separating the epimera. 



Another character of some importance is seen in the relative 

 lengths of the first and second tarsal joints. In Lathridius the 

 second joint is distinctly longer than the first, while in Enicmus the 

 two joints are of equal or very nearly equal length. As a rule, the 

 prosternum is longer in front of the coxa? in Enicmus, the prothorax 

 is transverse and widened rather than narrowed toward the middle, 

 the antennae are shorter, and the lower surface more strongly sculp- 

 tured. These latter differences, however, become weakened or quite 

 disappear in one species or another, so that they are characteristic 

 only in a general sense. 



Our species, like the European, are sharply divisable into two 

 subgenera as follows: 



Prosternal process not elevated into a crest, the coxje more prominent. 



Subgen. Conithassa. 

 Prosternal process elevated into a crest, which surpasses the summits of the coxse. 



Subgen. Enicmus. 



The twenty two species known to me are as follows : 



.Subgenus < OMTIIASSA Thorn. 



Tibiae straight or nearly so in both sexes- 1. 



Tihise rather strongly arcuate in the male. 



Form elongate; prothorax as long as wide or nearly so, front angles lobed and 

 moderately prominent; elytra a little produced at the apex. 

 More elongate, elytra nearly twice as long as wide, intervals not at all costate. 



proteusicollis. 



