2o2 New American Species of the Genera 



Found by Mr. Thomas Nuttall on the bank of the Missis- 

 sippi river. In many of its characters it resembles the arcuata, 

 but is much smaller, and the colour is altogether different ; 

 the indentation of the head also is hardly perceptible. It is 

 rather larger than geminata Nob. which, as I have ascertained, 

 on close examination, has the elytra denticulated at tip. 



5. B. pusilla. Blackish-green ; front without any obvious 

 impressed line. 



Description. Body slender : head tinged with bluish, with 

 obsolete, rather distant, punctures ; excepting on the ver- 

 tex, where they are rather large and confluent ; frontal 

 impressed line obsolete : antenna, black : thorax somewhat 

 inequal ; transversely confluently punctured ; two slight, 

 dilated indentations placed longitudinally on the disk, and 

 a larger and more profound one on the lateral margin ; an 

 elevated, arcuated line extends from the posterior angle 

 almost to the middle of the lateral margin : elytra indented 

 at base, at tip rounded and minutely denticulated, the den- 

 ticulations not extending on the sutural or lateral edge. 



Length less than three-twentieths of an inch. 



This is so much smaller than either of the above species, as 

 to be distinguished readily by that character, without resorting 

 to any other. I detected it at the cantonment of Major Long's 

 party, on the Missouri. 



Trachys. 



1. T. ovata. Ovate, black; head without an indented line; 

 elytra without regular punctures. 



Description. Body very short, ovate, black : head without 

 the usual dilated indentation, but a very slight indentation 

 may be observed on close inspection, particularly on the 



