WESTERN AND SOUTHERN LIMITS. 141 



commit local ravages on the Pataha River, at a point 40 miles northeast 

 of Walla Walla, there seems no doabt but that scattered broods inhabit 

 the valley of the Snake River, and may originate in the south, near Fort 

 Boise, or even flv over the Bitter Root Mountains from Central Mon- 

 tana. It is more probable that the whole valley of the Snake River, 

 where the soil is fertile, is inhabited by locusts, from its source in the 

 Rocky Mountain Range. Lewiston is said to have been visited by lo- 

 custs, and a large swarm appeared during the past summer in Baker 

 County, Oregon ; but the westernmost point to which the locust is 

 known to have reached is Camp Harney, about 175 miles south of 

 Umatilla, in longitude 118o 30' west, latitude 43° 30' north. At this 

 point it has o^casionallv abounded, so that in certain years it has been 

 impossible for the garrison to cultivate gardens. Beyond this meridian 

 the Rocky Mountain locust has not been traced. It is not probable that 

 flights have f^ver been borne by winds to the eastern flank of the Cas- 

 cade Range in Oregon and Washington Territory, as the desert, hot, 

 dry, grassless region which forms the western edge of the Great Plains 

 of the Columbia, as have been observed by us, is much like the desert 

 region of Nevada, with nothing but sage-bushes to support locust-life. 

 It is not probable that any swarms pass over the Cascade Range or the 

 Sierra Nevada, and indeed there are positive facts to the contrary, as 

 will be seen in our chapter on the migration of the locust. 



The next well-established locality in the western limits of the Rocky 

 Mountain locust is a point on Humboldt River, a little west of Hum- 

 boldt Station, where it was observed in considerable numbers by Mr. 

 Thomas in 1871. No specimens of Caloptemis spretus have been found 

 in the southern portion of Nevada, except that it has been reported at 

 Saint Thomas, near the Utah line, and not very far from Saint George, 

 Utah, where we know the species has been observed. It is evident, 

 therefore, that the migrations of this species in this latitude do not ex- 

 tend farther west than the eastern base of the Sierra Nevada, and then 

 only as straggling swarms from Northern Utah or Southern Idaho, aiid 

 chiefly along the line of the Central Pacific Railroad. 



SOUTHERIT LIMITS. 



The data we have been able to obtain for determining this line are very 

 limited in number, and by no means satisfactory ; in fact, we may say 

 that, so far as locust movements are concerned, this is almost terra incog- 

 nita. All we can say in reference to this line is that they have been 

 known to cross the Rio Grande at Eagle Pass, and penetrate a mile and a 

 half into Mexico; that they have been observed in Western Texas as far 

 as the settlements have extended; that they have penetrated New Mexico 

 on the northeast as far as Las Vegas and Fort Union, and have passed 

 down in the mountain region from Colorado to Taos, and possibly 

 farther south. 



