194 The Rocky Mountain Locust. 



injury is done in all parts of the country, by species 

 indigenous to the different localities, but which in ordinary 

 seasons do not attract any special attention. 



The principal depredator in such cases, in the Mississippi 

 Valley, is the wide-spread Red-legged Locust, already 



[Fig. 37.] 



Differential Locust. 



described and illustrated, (p. 14), and so often confounded 

 with the true migrating Rocky Mountain species. The 

 next most injurious is the Differential Locust {Caloptenus 

 differ entiaUs,W alk., Fig.37), a species at once distinguished 

 in the more typical specimens, from the preceding, not only 

 by its larger size, but by its brighter yellow and green colors. 

 The head and thorax are olive-brown, and the front wings 

 very much of the same color, and, without other marks, have 

 a brownish shade at base, the hind wings being tinged with 

 green; the hind thighs are bright yellow, especially below, 

 with the four black marks as in spretus^ and the hind shanks 

 [Fig. 38] are yellow, with 



black spines, and 

 a black ring near 

 the base. Next 

 in injuriousness 

 comes the Two- 

 striped Locust, 



Two-striped Locust. (Caloptenus Uvit- 



tatus, Say, Fig. 38), also a larger species, of a dull, olive- 

 green color, the hind thighs conspicuously yellow beneath, 

 and with two yellow lines extending from above the eyes 



