52 EEPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 



vein apparent. The wings pellucid, but when living have next the base 

 a bluish-white tinge ; a larger portion of the nerves and nervules dark. 

 The black stripe on the side of the head and pronotum nearly always 

 apparent, even in the darkest individuals 5 head and anterior lobes of 

 the pronotum with the velvety appearance, so marked in spretus^ but 

 here dark or olive brown, without the reddish cast so common in that 

 species ; the pale, oblique, metathoracic ray usually apparent, but often 

 obliterated. 



There are no reliable characters by which to distinguish it from the 

 female of femur-rubrum; the posterior lobe of the pronotum is usually 

 less conspicuously punctured, agreeing in this respect with spretns. 



Male. — Differs from spretus in being smaller, pronotum rather more 

 constricted and subcylindrical ; eyes more rounded and prominent ; the 

 notch at the tip of the last ventral segment less distinct, sometimes al- 

 most obliterated ; more of the nerves of the wings dark. 



From the male of femur-rubrum it differs in usually having longer 

 wings ; in some individuals they are as long, proportionably, as in any 

 specimen of spretus; in others, little or no longer than in femur-rubrum; 

 in the more slender form, and smaller size j in having the apical seg- 

 ment of the abdomen narrowed and notched at the tip j in having the 

 cerci broad throughout, and shaped as in spretus; in having the tooth- 

 like api)endages at the base of the super-anal plate shortened and broad- 

 ened, and with a longer union at their base. 



It is evident from these characters that atlanis is an osculant species 

 (or variety) intermediate between spretus and femur-rubrum, partaking 

 largely of the characters of each, and, in a few respects, differing from 

 both. The female approaches very near femur-rubrum, scarcely show- 

 ing varietal differences from the female of that species, while on the 

 other hand the male approaches much nearer spretus than it does femur- 

 ruhrum, as shown by the character of the terminal segment, the form of 

 the cerci, and the length of the wings. The local species heretofore 

 mentioned, which belong to this restricted group are, in all probability, 

 offshoots from spretus or femur-rubrum, the particular direction of the 

 variation depending upon the peculiar condition of the locality. 



The popular names of these species are as follows : 



C. femur-rubrum has generally been and is still known as the " Eed- 

 legged locust"^ or, which is better, the "Common Eed-legged locust." 



G. atlanis was first described from the IsTew England States, but as 

 the species is not confined to the Atlantic slope, and the term Atlantic 

 might convey a wrong idea, we have concluded to call it the " Lesser 

 locust," in reference to its smaller size. 



C. spretus is known by several popular names, as " The Hopper," 

 '' Army grasshopper," " Eed-legged locust," " Mormon locust," " West- 

 ern locust," " Hateful grasshopper," and " Eocky-Mountain locust." 

 The last name, which Mr. Eiley suggested as the most appropriate, is 

 now generally adopted, and has been accepted by the Cooimission. 



