Occasional Papers of the Museum of Zoology 7 



on all sides from the surrounding prairie ; their surface lies 

 from 400 to 800 feet above the plain, with a maximum eleva- 

 tion of 2,860 feet. They are covered with forests of aspen, 

 balsam poplar, oak, paper birch, and alder, in most places 

 with dense undergrowth ; most of the trees are small on 

 account of the destructive fires which have swept this region 

 in the past. Some farming is carried on, and grassy or shrubby 

 clearings surround the farmhouses scattered through the hills ; 

 abandoned clearings are also found in different stages of rever- 

 sion to natural conditions. The region is well watered and 

 poorly drained ; many of the valleys are occupied by small 

 glacial lakes, bordered by marshes or by sandy or gravelly 

 beaches, and in the moist depressions there are numerous 

 meadows and swales of tall grass and herbage. 



C. Mouse River J 'alley (Bottineau, Bottineau County). — 

 The only collecting done in this area was at Bottineau, near 

 the southwestern foot of the Turtle Mountains. The region 

 is an old lake plain, almost unbelievably level and monotonous ; 

 so far as vegetation and insect fauna are concerned it seems 

 to be practically the same as the prairie in the vicinity of Devils 

 Lake. Very little of the original prairie vegetation remains 

 in this vicinity; most of the land is under cultivation, and 

 much of the remainder is overrun with dense mats of Russian 

 thistle.^' During the summers of 19 19 and 1920 crops in this 

 vicinity were almost completely destroyed by plagues of grass- 

 hoppers, and for some years previous they had been very 

 troublesome. An examination of the fields in the neighbor- 

 hood during both summers showed that Mclanoplus mcxicanus 

 atlanis, Mclanoplus hivittatus and Cainnula pellucida were the 

 most abundant species in the swarms of grasshoppers which 

 covered the plants and the ground beneath ; other common 



^ Salsola kali L., var. tciiiii folia G. F. W. Mey. 



