450 COLEOPTERA OF NORTH AMERICA. 



Tribe IV.— DIROTOGNATHINI. 



Rostrum longer than the head, slightly flattened. Mandibles 

 rather prominent. Mentum very small, trapezoidal, not retracted, 

 maxillae and ligula entirely exposed. Thorax with feeble ocular 

 lobes. Metasternal side pieces narrow connate with the sternum, 

 with very slight traces of suture. 



These few characters serve to distinguish this tribe as repre- 

 sented in our fauna, to which may be added : Mandibles promi- 

 nent, laminiform at tip, inner edge strongly bidentate, outer edge 

 arcuate, with a groove and a scar-like space near the base, apex 

 truncate, scar terminal, small, very narrow and transverse, de- 

 ciduous pieces short, broader at tip and obliquely truncate. Men- 

 tum very small, supported by a distinct peduncle which is rather 

 short. Metasternum rather short. 



We are entirely unable to place this tribe in or near any of 

 those indicated by Lacordaire, further than to state that it is 

 Phanerognath Synmeride and belongs to the first section of the 

 latter Phalanx. 



One species, Dirotognathus sordidus, occurs in California and 

 Arizona. 



DIVISION II. 



In this division are contained all those genera in which the 

 mesosternal side pieces are diagonally divided into two nearly 

 equal pieces, the outer of which (epimeron) cuts .off the inner 

 (episternum) from any contact with the elytral margin. The 

 metasternal episternum is usually moderately broad, the suture 

 distinct in its entire length, rarely narrow, and in one genus the 

 suture is entirely obliterated. In every case, however, the ante- 

 rior end of the metasternal episternum is suddenly dilated, caus- 

 ing on one side an emargination of the elytral margin (which is, 

 however, evanescent), while on the inner side an acute triangular 

 process of varying length occupies a space between the meso- 

 sternal epimeron and the body of the metasternum. 



The antennal scrobes vary in form, position, and extent. The 

 mentum is, in all of our genera, at least moderate and visible, 

 excepting Eudiagogus and Coleocerus where it is small and much 

 retracted, allowing the parts of the month to be visible. The 

 beak at tip exhibits two distinct forms. In the one the genag are 



