194 COLEOPTERA OF NORTH AMERICA. 



nished with pores, whicli are difi'used on the sides, or concen- 

 trated in a fovea on the inferior margin or at its extremity. 



Head immersed in the thorax to the eyes, which are ellip- 

 tical, and never emarginate; labrum small, prominent; man- 

 dibles short, stout. 



Prothorax with the side pieces not separate from the upper 

 piece; coxal cavities separated by the prosternum, widely 

 open behind; prosternum prolonged behind, fitting into the 

 mesosteruum, or even the metasternum. 



Mesosternum short, excavated, so that the visible part is 

 frequently divided into two portions, which complete the 

 anterior coxal cavities ; side pieces large, diagonally divided ; 

 epimera narrowly attaining the coxae. 



Metasternum with the side pieces narrow ; epimera visible. 



Elytra covering the abdomen, or leaving only the pygi- 

 dium exposed; epipleuras narrow ; wings large. 



Abdomen with five ventral segments, the first and second 

 connate, the others free ; the fifth joint frequently emarginate 

 in the males, leaving a small sixth joint visible. 



Anterior coxte separate, small, globular, received between 

 the pro- and mesosternum, with the trochantin distinct; 

 middle coxsd separate, globular, with the trochantin distinct; 

 posterior coxas transverse, usually nearly contiguous, con- 

 cave behind, dilated into a plate partially covering the 

 femora when retracted. 



Legs short; tibias usually slender, with two small terminal 

 spurs; tarsi 5-jointcd, the first four joints with more or 

 less developed membranous appendages beneath; onychium 

 none. 



The species of this family are, in general, elongate in form, and 

 ornamented with metallic colors; the larvae perforate the stems of 

 living plants, and the perfect insects are found partly on flowers, 

 partly sunning tlieinselves on trees, during the hotter seasons of 

 the year. 



A monograph of the species belonging to our fauna has been 

 published by Dr. LeConte in the Transactions of the American 

 Philosophical Society, vol. XI, in which, with some modifications, 

 the classification of Lacordaire was adopted ; the characters of 

 the groups have here been farther modified by the views of DuVal, 

 and the divisions proposed are based upon renewed observations, 

 though the groups themselves arc scarcely different from those 

 previously adopted. 



