28 



The Rocky Mountain Locust. 



ish-gray parts are bright green. These green individuals 

 are conspicuous among their brown brethren. In the Mis- 

 sissippi Valley they generally constitute about one in a 

 thousand of the progeny of invading swarms; but I have 

 not noticed them among the fresh arrivals from the moun- 

 tains. The green endures from the larva to the perfect 

 state, and I have designated this variety as viridis. It is 

 but a marked colorational variety, in a species which has 

 not heretofore been known to present these colorational 

 differences, and no one having a true conception of the 

 differences of the three species just defined would think 

 of placing this latter on the same grade. 



THE SPECIES IS PURELY AMERICAN. 



As the idea prevails among many of our farmers- that 

 our Rocky Mountain Locust is identical with the devastat- 

 ing species of the Old World, and Mr. Z. S. Ragan, in an 

 otherwise excellent essay, read at the annual meeting of 

 the Missouri State Horticultural Society for 1875, gives it 

 as his opinion that our locusts " came over from Asia via 

 Behring's Strait, to British America, and thence extended 

 from time to time over Washington Territory, Oregon, 

 California, Utah, Idaho, Montana, Wyoming, Dakota,. 

 Nevada, Colorado, Arizona, New Mexico, Texas, Kansas, 

 Indian Territory, Nebraska, part of Missouri, Iowa, Min- 

 nesota and Wisconsin ;" it maybe well to insist here that 

 there is no foundation whatever for such an opinion, and 

 that spretus is a purely American species, occurring in no 

 part of Europe or Asia. 



