8 University of Michigan 



species which were present in numbers were Melanoplus infan- 

 tilis, Melanopliis packardii, and Melanoplus dawsoni. 



Missouri Plateau Section of the Great Plains Province. — 

 A. Not^thern Portion (Buford and WilHston, WiUiams 

 County). — During the latter part of July, 1920, Miss Thompson 

 and Miss Olson spent a few days in this vicinity. Collecting 

 was done chiefly on the flats of the Missouri River Valley and 

 on the slopes and crests of the bluffs overlooking them. 

 Orthoptera were abundant in the cultivated fields and among 

 the xerophytic vegetation along the bluffs, but there were 

 comparatively few on the clay bottom lands. These localities 

 are the only ones where any collecting was done in the north- 

 western part of the state. 



B. Southzuestern Portion (Medora, Billings County; Ami- 

 don, Slope County). — Four general topographic types are rep- 

 resented in this region : uplands, lowlands along the stream 

 valleys, bad lands, and river terraces. The upland areas occupy 

 most of the region ; their surface is a rolling plain, the eleva- 

 tion of which varies from 2,700 to nearly 3,200 feet above 

 sea level. The surface of the plain is studded with high buttes, 

 standing 400 to 600 feet above the level of the surrounding 

 plain, and forming a conspicuous feature of the landscape. 

 The upland is well drained, being covered with a network of 

 small watercourses, the majority of them dry throughout the 

 year ; lakes and ponds are of rare occurrence. The most prom- 

 inent topographic feature of the region is the valley of the 

 Little Missouri River and its bordering strip of Bad Lands. 

 The river at Medora lies over 400 feet below the plains. Its 

 valley at the bottom is one-half to one mile wide, and stretch- 

 ing away on each side are broad terraces several miles in 

 width, intermediate in height between the lower valley and 

 the plains above. The Bad Lands border the valley on each 



