430 COLEOPTERA OP NORTH AMERICA. 



Body rather elongate, or pyriforni, front and middle coxae con- 

 tiguous, conical, prominent. Prothora.x without side margin, not 

 excavated beneath. Mesothorax with side pieces diagonally- 

 divided, epimera not ascending. Metathorax with narrow parallel 

 side pieces. 



Our genera are as- follows : — 



Pygidium covered by elytra ; 



Elytra punctured irregularly. Auletes. 



Elytra striate. Eugnamptus. 



Pygidium exposed, elytra witli stripe of punctures. Rhynchites. 



Auletes and Khynchites occur on both sides of the continent; 

 Eugnamptus in the Atlantic region only. B. velatus, from 

 Nevada, is remarkable for the male having two long pectoral 

 spines as in many species of Centrinus. 



Sub-Family II.— PTEROCOLIN.E. 



A single species constitutes this sub-family. On account of the 

 anomalous characters its place in the series of Rhyncliophora has 

 been changed from time to time, without very satisfactory results. 

 The latest authority, Lacordaire, deceived by the broad form of 

 l)ody and ascending side pieces of the mesothorax, placed it in 

 the neighborhood of Ceutorhynchus. A study of the mouth 

 organs, as well as the antennse, shows that it is allied to Auletes 

 and Rhynchites, while the other differences require it to be re- 

 ceived as a very peculiar and distinct type. 



It differs from the genuine Rhyuchitidie by the antennas inserted 

 much nearer the eyes, which are suddenly but not deeply emargi- 

 nate in front. The side margin of the prothorax is acute and 

 well defined, and the under surface, with the anterior part of the 

 mesothorax, is excavated, forming a large cavity for the reception 

 of the front and middle legs. The elytra are sculptured with 

 wide shallow grooves, which are confus-edly punctured ; the epi- 

 pleurfe are distinct; the tips are widely dehiscent and separately 

 rounded, exposing parts of three dorsal segments, all corneous 

 and densely punctured. Front and middle coxae small, rounded, 

 widely separated, not prominent; posterior coxaB separated, trans- 

 verse, intercoxal process broad. Tibia? with two distinct apical 

 spurs, tarsi dilated, clavrs appendiculate. Ventral segments 

 short; pygidium less convex in the %, and strongly inflexed. 



