LOCUST OBSERVATIONS IX THE KOBTHWK8T. 59 



they keep their wings clattering and rattling to such an extent that one 

 would suppose they were rattling into pieces. 'We did some collecting 

 at Custer's battle-field, where we took a Large variety of species, as well 

 as in most cases a large series of specimens. Hen- we also observed 

 to a great extent the partiality which certain species exhibited in 

 the selection of special food -plants. Again, at Junction City, Mont., 

 we made some collections, adding a few to the list of species taken. 

 Here, for the first time, we took several specimens of a specie of 

 CEdipodince belonging in the genus Mestobregma, and which almost 

 exactly imitates in color a species of Psoloessa which we took on the Lar- 

 amie River, south of Laramie City. While these two insects so closely 

 resemble each other in color they are quite distinct, and as Scudder has 

 subdivided the geuus (Edipoda they fall into distinct geuera. The two 

 species in question, however, are both partial to the same food-plant, 

 viz., the white or sweet sage, and' thus far I have found neither away 

 from where this plant abounds. 



We again collected at a point on the Yellowstone River about mid- 

 way from Trail Creek to the National Park, at the Mammoth Hot 

 Springs, and at Henry's Lake. It was at the former of these localities 

 that we found the Mestobregma most abundant. 



While passing along the road near Gardiner, a new town, which is 

 to be the terminus of the Park brauch of the Northern Pacific Railway, 

 we captured a few specimens of the same species of light-blue-winged 

 Trimerotropis that I took last year at Fort Benton, thereby extending its 

 range at least to the southern border of Montana. It appeared to be 

 quite rare even in its special haunts, viz., a light, almost bare, whitish, 

 alkaline soil destitute of rocks. It was also taken in the Lemhi Valley 

 of Idaho. At this same locality several other species of closely allied 

 locusts were taken. After crossing the main Rocky range to the west 

 side a change in the comparative abundance of some species and in 

 the total absence or replacement of other species was observed. 



While on the eastern slope we found Vircotettix carlingianus quite 

 abundant and ('. undulatus rather rare, on the western side of the divide 

 we found just the reverse. 



The large, red-winged Hippiscus which on the east side is everywhere 

 so abundant, and in fact all the red-winged forms, have thus far been 

 exceedingly rare, only four specimens having been seen during the five 

 days that have passed since crossing the summit. A species which, on 

 the eastern side, was met with but occasionally has become quite plenti- 

 ful. It is perhaps what Mr. Scudder has called Prtmdia wallida. 



Thus far we have found locusts to be most numerous in species at an 

 elevation varying from 2,500 to 0,000 feet above sea level, and on the 

 bench-lauds in preference to either bottom or mountain lands. While 

 most of the Caloptenus and Pezotettix were partial to moist localities 

 where vegetation was rankest, the GuUpodimv and Mnwbothrini. \-c. 



