56 



The Rocky Mountain Locust. 



tains in Colorado it often gets chilled in passing the snows, 

 and thus perishes in immense numbers. The bears of this 

 locality desire no better condiment wherewith to season 

 their usual repasts. 



My own belief is that the insect is at home in the higher 

 altitudes of Utah, Idaho, Colorado, Wyoming, Montana, 

 Northwestern Dakota, and British America. It breeds in 

 all this region, but particularly on the vast hot and dry 

 plains and plateaus of the last named Territories and on 

 the plains west of the mountains ; its range on the east 

 being bounded, perhaps, by that of the buffalo grass. Mr» 

 Wm. N. Byers, of Denver, Colorado, shows that the 

 insects hatch in immense quantities in the valleys of the 

 three forks of the Missouri river and along the Yellow- 

 stone, and that, when fledged, they move on from there 

 in a southeast direction at about the rate of 10 miles per 

 day. The swarms of 1867 were traced, as he states, from 

 their hatching grounds in West Dakota and Montana, 

 along the east flank of the Rocky Mountains, into the 

 valleys and plains of the Black Hills, and between them 

 and the main Rocky Mountain range.* 



In all this immense stretch of country, as is well known, 

 there are extensive tracts of barren, almost desert land, 

 while other tracts for hundreds of miles bear only a scanty 

 vegetation ; the short buffalo grass of the more fertile 

 prairies giving way, now to a more luxurious vegetation 

 along the water courses, now to the sage bush and a few 

 cacti. Another physical peculiarity is found in the fact 

 that not only does the spring on these immense plains some- 

 times open as early, even away up into British America, as 

 it does in Chicago, or exceptionally even in St. Louis, but 

 the vegetation is often dried and actually burned out 



* See Hay den 1 s Geol. and Geogr. Survey of the Territories, 187J, pp. 282-3. 



