MORGAN HEBARD 339 



Further studies of the penis are proving more and more con- 

 clusively that this organ can not be disregarded when considering 

 species of the genus Melanoplus. In fact it would otherwise have 

 been impossible to determine safely as distinct species or races 

 several of those here treated. We therefore give the following key 

 based on the characters shown by the penis, as well as figures of 

 this organ for all of the new forms we are describing. It must be 

 remembered, however, that external characters often distinguish 

 many species from all others quite as safely and we believe that 

 when such is the case they should be given precedence over 

 features which can not be determined for individual specimens 

 without dissection. Indeed, among the species of the Viridipes 

 Group, the structure of the penis is so similar in viridipes viridipes, 

 viridipes eurycercus and longicornis that attempt to separate these 

 insects on the basis of characters of the penis should not be made, 

 but they are readily distinguished by features shown by the male 

 cerci. In other cases in this group, knowledge of the distribution 

 of the species is of distinct assistance in locating certain of them. 



Penis with a stout base. 



A. This base surmounted by a pair of horizontal triangular proc- 



esses directed latero-caudad. A pair of very slender 

 attingent median processes, very elongate and whip-like, 

 are directed dorsad and curve cephalad, then ventrad. 



gracilis Bruner 

 AA. This base with processes projecting vertically. The pair of 

 median aciculate processes erect or sheathed by the pair 

 of proximal processes. 



B. The proximal processes with concave or flattened surfaces 



facing caudad. The median processes erect, aciculate. 



C. Basal portion much less elevated caudad, so that the two pair 



of dorsal processes project much more conspicuously. 



D. The proximal processes rounded triangular with caudal sur- 



faces not conspicuously concave, less ear-like. 



E. The proximal processes relatively small. 



F. Male cercus broader, not or but feebly widened (in viridipes 



viridipes only) distad. 



G. Male cercus larger, tapering but still broad distad with apex 



rounded. Caudal femora usually (but by no means al- 

 ways) heavily marked. 

 H. Male cercus short. New York to Michigan, south in Appa- 

 lachians to North Carolina. . . viridipes eurycercus Hebard 



TRANS. AM. ENT. SOC, LX. 



