156 COLEOPTERA OF NORTH AMERICA. 



and is then expanded again, forming two diverging lobes ; the 

 anterior part of the head is vertical ; the mouth inferior, and 

 applied to the prosternum in repose ; the mentum is large, trian- 

 gular, and corneous. The prothorax is lobed at the base, receiv- 

 ing the convex bases of the elytra. The prosternum is broad in 

 front, with oblique sutures, cuneate behind, and scarcely angulated 

 behind the coxa? ; the mesosternum is small, completely and fre- 

 quently widely divided ; the metathoracic epimera are small, and 

 frequently not visible. The hind coxae are but slightly dilated 

 internally, narrowest at the middle, and broader externally, with 

 the anterior margin more or less concave, and the hind margin 

 not oblique. The legs are contractile, and the claws are strongly 

 toothed, or even cleft, except in Taphrocerus, where they are 

 connate at base, and simple. 



Two groups exist in our fauna, as follows : — 



Antennae free. Agrili. 



Antenna received in grooves. Beaches. 



Group I.— Agrili. 



The body is always elongated ; the prosternum is pointed 

 behind ; the anterior and middle coxa? are separated by about 

 the same distance ; the anterior margin of the hind coxa? is very 

 distinctly concave, and the prolongation of the abdomen reaches, 

 but does not extend along, the side pieces of the metathorax; 

 there are no grooves on the under surface of the prothorax, for 

 the reception of the antennas ; the tarsi are long or moderate ; 

 the scutellum is transverse and acuminate in our genera, which 

 are but two in number : Agrilus is generally diffused ; Corasbus 

 is represented by but one species, C. cogitans, in the Atlantic 

 States. 



Hind tarsi with first joint scarcely elongated. Cor^ebus. 



Hind tarsi with first joint as long as the three following. Agrilus. 



Group II.— Braches. 



I formerly considered this as identical with the European group 

 Traches, but the characters are sufficient to warrant its being 

 placed as distinct. The body is rarely elongated, usually broad 

 and ovate ; the middle coxaa are a little more distant than the 

 anterior ones, and the mesosternum is very widely divided ; the 

 prosternum is very variable in form ; the anterior margin of the 



