I5O ARTHUR G. VESTAL. 



cattle. It is of common occurrence on the north shore of Douglas 

 Lake, and near Munro Lake, several miles north. In this type 

 of meadow Melanoplns atlanis and Stenobothrus curtipennis are 

 of about equal abundance. M.femur-rubrum was not taken, but 

 is more abundant in such places in other localities than is M. 

 atlanis, M. differential is is typical in meadow habitats, and 

 M. bivittatus is found sparingly. 



Arrangement of the Associations as Habitats. 



The associations of any particular region may be placed in 

 groups with respect to several well-known criteria. One of the 

 prevalent methods is to consider together all associations which 

 are genetically related, which form a developmental series, each 

 stage being succeeded by the next in order, until the ultimate or 

 climax association is reached. Another mode of classification is 

 geographic, placing together all associations of like geographic 

 distribution, all typical of a definite climatic region, an ecological 

 province. Another grouping is based upon growth-form : by this 

 treatment associations dominated by plants of similar growth- 

 form, indicating physiological likeness, would be considered 

 similar, regardless of geographic or successional relationships. 

 The common division of associations of a region into climatic or 

 geographic, and edaphic or local, is based upon local distribution 

 or habitat. The grouping into aquatic and terrestrial is a 

 grouping based upon habitat in a larger sense: the medium of 

 life is the important feature. Finally it is necessary to distin- 

 guish between primary, original or native associations, and 

 secondary, ruderal or cultural associations, wherever human 

 influence has modified primeval conditions. These different 

 groupings are not at all parallel, but form a complex. To orient 

 an association with respect to others of the same region it is 

 necessary to find its place in this complex. In a regional treat- 

 ment it is usually necessary to consider all of these criteria. For 

 different purposes, different bases of classification may be empha- 

 sized, but in no case should one basis be confused with another. 



For the purpose of the present study, in which the plant associa- 

 tions are considered mainly as habitats for grasshoppers, two 

 bases of classification receive emphasis. The first is with respect 



