PERMANENT BREEDING GROUNDS. 133 



that the locust breeds ia the belt of land lying between the northern 

 limits of prairie and the southern limits of true forests, also iudicated 

 on the map. 



Tbis region of the Great Plains extends southward, embracing the 

 area drained by the Missouri River and its tributaries and headwaters, 

 west of the 203d meridian, and including the entire Yellowstone Valley 

 except the Belt Mountains and their spurs, the wooded, region and 

 mountains about the Yellowstone Lake, and the Wind Eiver Mountains 

 southward, also including the more elevated portion of the plateau from 

 which the Black Mountains rise. 



Although the Rocky Mountains, Bitter Root, and Wind River Ranges 

 are excluded partly because we know little of those mountains, which 

 have not been explored by entomologists, yet there are doubtless a good 

 many canons, river valleys, and parks lying at their base where the 

 locust may locally abound, and from which in years of unusual abun- 

 dance swarms may pass out to join those originating in the areas where 

 they are known to multiply to an excess. 



Of the large area forming over half of the Territory of Idaho, and 

 lying between the Bitter Root Range and the valley of the Snake River, 

 we know nothing whatever. Ko naturalist, much less entomologist, 

 has explored this region, which is mainly drained by the Salmon River, 

 though there are small settlements scattered through it, such as Lemhi, 

 Florence, Elk City, Millersberg, Oro Fino, and Coeur d'Aleue Mission 

 on the north, from whence we have been able to obtain no information 

 whatever as to the presence or absence of the locust. The origin of the 

 swijrms of locusts that have in certain years locally devasted the region 

 about Lewiston, Walla Walla, and the Pataha Valley is not certainly 

 known, though we suppose that they have originated in the Snake 

 River Valley, south of latitude 45^ 30', though some of them may have 

 hatched in the Bitter Root Valley, or even in the valleys on the western 

 flanks of the range. There seems good reasons for regarding the entire 

 valle}^ of the Snake River, from near its headwaters near Henry^s Lake 

 and the Teton Range to a little below the mouth of Powder River, in 

 Oregon, as more or less permanently inhabited by the locust, excepting 

 the dry and barren region northwest of Great Salt Lake, concerning 

 which we have no information. 



We have ventured to indicate on the map a large area of the Snake 

 River Valley, west of the 14th meridian, as a permanent and native breed- 

 ing ground, from data, however, much more meager than we could 

 desire. 



Of the region indicated on the map and lying directly north of 

 the Great Salt Lake, we have such lull and satisfactory information, 

 derived from the personal examination of two of the Commissioners, that 

 we feel sure that the limits are accurate so far as drawn, though the area 

 may prove to be larger than we have ventured to indicate. Records 

 from the year 1851 show that with rare exceptions the Malade and 



