AMERICAN PHILOSOPHICAL SOCIETY. 525 



SPHERACRA Say. 

 Elytra entire ; tibiae emargiaate; terminal joint of the tarsi 

 profoundly bilobated ; nails simple ; head as long behind the eyes 

 as before them ; thorax subcylindric ; antennse much shorter 

 than the body; basal joint much shorter than the head, 

 joints excepting the second not very unequal in length, subcy- 

 lindric; labrum emarginate ; palpi with the terminal joint some- 

 what fusiform, subacute ; mentum with a prominent acute cen- 

 tral tooth. 



S. DORSALis Fabr. — " Black ; elytra striate, testaceous ; suture 

 broadly black. 



Inhabits Carolina. 



Museum of Mr. Bosc. 



Smaller than 0. angustata. Antennse testaceous ; head black, 

 polished, broader than the thorax ; thorax cylindrical, obscurely 

 ferruginous; elytra striate, testaceous; suture broadly black, 

 hardly attaining the tip ; body black ; feet testaceous." Fabr. 



Odacantha dorsalis Fabr. Syst. Eleuth. 1, 229. 



In my specimen the head only is black, or rather of so deep a 

 rufous as to appear black, excepting the tip and base. [413] 



This well known species was referred by its discoverer, Fabri- 

 cius, to his genus Odacantha ; in which arrangement he was fol- 

 lowed by Dejean, who, however, was fully aware of its generic 

 difference from the 0. melanura, Fabr. Dejean, in his observa- 

 tions on the genus, says, " that in consequence of the joints of 

 the tarsi being less filiform than those of the type of the genus, 

 almost triangular, the penultimate one deeply bilobate and the 

 extremities of the elytra rounded, it would be perhaps proper to 

 make a new genus of this insect." In this remark I perfectly 

 coincide, as I cannot see the propriety of joining, in the same 

 genus, two insects whose characters in the artificial system place 

 them in different families, though it cannot be denied that they 

 have many, more intimate, natural affinities. 



I had written the above with the expectation of introducing 

 a new species, in an insect which, in form and color, resembles 

 the dorsalis exceedingly to the eye, excepting in size ; but on 

 close examination it proves to be widely distinct. 



[This genus was previously described as Leptotrachdus Fabr. 

 — Leg.] 

 1834.] 



