300 COLEOPTEEA OF NORTH AMERICA. 



Sub-Group 2. A CHRYSONES. 



Slender sub-cylindrical species, with slightly dilated palpi ; 

 the head short, and front perpendicular as in Oemes; the front 

 coxae globose, prominent (contiguous in Achryson), not angulated 

 externally, trochantin not visible ; the middle coxae are also 

 prominent, closed externally, the mesosternum is moderately wide, 

 truncate at tip in A. surinamum, narrow and sub-triangular in the 

 Texan A. concolor ; the elytra are armed with a terminal spine 

 in the former, but are rounded in the latter. The 5th ventral 

 segment of is truncate, but not shorter than the 4th. 



A. surinamum (Linn.), (S. circumflexus Fabr.) is found from 

 the Middle States to Mexico and South America ; it is a slender 

 pale-brown insect, with dark angulated lines on the elytra. 



Sub-Group 3. G R A c i L i JB . 



Very small slender species of piceous color, very finely punc- 

 tured and pubescent, constitute this sub-group. The head is 

 short, as in the other sub-groups, the palpi very unequal, the 

 labial short, the maxillary long with the last joint triangular, 

 obliquely truncate so as to appear pointed ; eyes large, coarsely 

 granulated, deeply emarginate, almost divided ; front coxae very 

 prominent, nearly contiguous, the prosternum being narrow, and 

 pointed behind ; the coxal cavities are sub-quadrate ; the middle 

 coxae are prominent, separated by the triangular mesosternum, 

 the cavities are angulated externally, but the epimera are very 

 small, and do not fully reach the coxae; the episterna of the meta- 

 thorax are linear ; the 1st ventral segment is somewhat longer 

 than usual. The legs are short, the thighs thick and clavate, 

 the 1st joint of the hind tarsi longer than the 2d and 3d. 



The mesonotum is covered with stridulating surface ; it is 

 less transverse than usual, nearly quadrate, and finely margined 

 at the sides. 



The antennae are hairy, in $ longer, in 9 shorter than the body. 

 Gracilia pygmsea has been introduced in articles of commerce 

 from Europe. G. manca is very rare in the Middle States, and 

 differs by the prothorax being more rounded on the sides, and the 

 elytra a little shorter than the abdomen. 



