170 COLEOPTERA OP NORTH AMERICA. 



minatus Randall. The genus Sericosomus, placed by European 

 authors near Dolopius, appears to me more nearly allied to Co- 

 rymbites. 



Group II.— Melanotl. 



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

 having the front moderately convex, margined anteriorly ; the 

 mouth anterior; the antennce 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, for 

 which I unfortunately adopted the more recent name Cratonychus 

 in my revision of the Elateridse of the United States. 



Group III.— Athoi. 



Here are to be placed all species having the front margined ; 

 the mouth anterior; the coxal plates narrow, gradually dilated 

 inwards, scarcely toothed ; the claws simple ; and the prosternal 

 sutures nearly straight, double, though rarely excavated in front ; 

 the first joint of the antennas is moderate. The front is sometimes 

 not only margined, but deeply concave, by the margin being re- 

 fiexed ; in some species of Limonius the margin is almost obsolete 

 at the middle, establishing thus a transition to the group Corym- 

 bites ; the prosternal' lobe is sometimes obsolete, and the middle 

 coxae are in Campylus very approximate, so that the metasternum 

 becomes acute in front. The tarsi have sometimes the second 

 and third joints slightly lobed beneath. 



The body is usually slender, and rarely (Pityobius) of large size. 



Our genera are : — 



Tarsi with the first joint scarcely longer than the second. Limonius. 



Tarsi with the first joint elongated ; 



Prosternal lobe very short ; 



Metasternum acute ; antenna 11-jointed. Campylus. 



Metasternum obtuse ; antennae 12-jointed. Pityobius. 



Prosternal lobe long. Athous. 



Gambrinus Lee. is not sufficiently distinct from Limonius, nor 

 Pedetes from Athous. The males of Pityobius are remarkable 

 for the antennas having on each side a row of branches. Two 



