142 ARTHUR G. VESTAL. 



Hancock ('n), classifying these insects on the basis of habitat, 

 have been reviewed by Shelford ('126: 352). Biological surveys 

 of certain regions, as the Michigan surveys, have included local 

 distribution of grasshoppers (Adams, '06, '08; Ruthven, 'n; 

 Hart and Gleason, '07). Studies of animal communities have 

 included data on grasshopper distribution (Shelford, '120; Vestal, 

 '136). In these two studies not all of the associations of the 

 region were considered. In many of the above accounts the 

 concept of the plant association as a habitat has appeared inci- 

 dentally or not at all; this concept was used in a study of local 

 distribution of birds, by Gates ('11). In the present study all 

 the plant associations of the region have been included, and the 

 plant association has been used as the index of the habitat. In 

 general the results indicate that the important factors of local 

 distribution are, in initial stages of development of the vegetation, 

 physical conditions of the environment; in advanced stages, 

 vegetational conditions; in either case, the character of the plant 

 association is the index to local environmental conditions for 

 grasshoppers. Collection data are in another paper (Vestal, '130). 



Physiography of the Region. 



Douglas Lake is situated less than twenty miles south of the 

 northern tip of the southern peninsula of Michigan, in Cheboygan 

 county. There are two main physiographic types, the first 

 being old beaches and lake bottoms of the Nippissing and Algon- 

 quin Lakes, and the second morainic in origin. The soil of the 

 first type is almost pure sand; the relief is very slight. The 

 morainic lands have typical rolling topography; they are of 

 mixed composition, usually with loam or sandy loam surface soil. 

 Streams are small and few, but on the whole the region is well 

 drained, the soil being porous. Swamps occupy a very small 

 proportion of the area, and are usually drained. Undrained 

 swamps are few and small in the immediate vicinity. 



The lake is about four miles long, with irregular contour, and 

 lies north of a chain of lakes which in recent geological time 

 connected Lakes Michigan and Huron. Douglas Lake was 

 itself, previous to this time, a part of the connection. Much of 

 the shore line is sandy beach, with occasional sand-bars and spits, 



