186 COLEOrTEIlA OF NORTH AMERICA. 



Front flattened, not margined ; mouth, anterior ; 



Mesosternuiu declivous. Corymbites. 



Mesosternuui protuberant. Melanactes. 



Group I. — Agriotes. 



Tliis group, composed of species of moderate or small size, is 

 distinguished by tlie convex front, the edge of which is higher 

 than the labrum; the mouth is situated on the inferior surface of 

 the head, and is applied to the prosternum in repose ; the latter 

 is lobecl in front; the sutures are double, either concave outwai'ds 

 or nearly straight, somewhat excavated in front; the antennae 

 are slender, scarcely serrate, and the first joint is a little longer 

 than usual; the coxal plates are but slightly broader internally, 

 although sometimes almost suddenly dilated ; the tooth at the 

 insertion of the thighs is large. 



Our genera are: — 

 Front truncate, not margined behind the labrum, although higher than 

 it ; claws simple ; 



Margin of prothorax deflexed in front. Agriotes. 



Margin of prothorax straight. Dolopius. 



Front margined ; 



Claws and tarsi simple. Betarmon. 



Claws pectinate, tarsi slightly lobed. Glyphonyx. 



To Dolopius, as here defined, belong D. macer Lee, lateralis 

 Esch., and simplex Motsch. ; to Betarmon belongs only Elater 

 bigeminalus Randall. The genus Sericosomus, placed by Euro- 

 pean authors near Dolopius, appears more nearly allied to 

 Corymbites. 



Group II. — Melanoti. 



In this group are contained species of moderate or small size, 

 having the front moderately convex, margined anteriorly; the 

 mouth anterior; the antennae serrate, with the first joint of the 

 usual size ; the prosternum is lobed in front ; the sutures are 

 double, and concave outwards; the coxal plates are gradually 

 dilated inwards, and toothed at the origin of the thighs; the 

 tarsi are not lobed beneath, and the claws are strongly pectinate. 



Our species are numerous, and all belong to Melanotus. 



Group III.— Athoi. 

 Here are to be placed air species having the froat margined; 

 the mouth anterior; the co.xal plates narrow, gradually dilated 



