GRASSHOPPERS IX RELATION TO PLANT ASSOCIATION 1 75 



but more usually range over much wider areas (Shelford, 'n: 

 606). Species of very general local distribution within a re- 

 stricted area are likely to be very generally and very widely 

 distributed geographically, and are the species which most 

 frequently invade ruderal and cultural growths, and which tend 

 to replace other species with the spread of civilization. Species 

 of closed associations show more evident local and geographic 

 relation to the vegetation than species of open associations, in 

 which local physical conditions dominate (cf. Shelford, 'i2a: 

 89, 90). 



Seasonal Relations. 



Distribution of animals in space is more or less affected by 

 distribution of animals in time. In dealing with the latter it 

 seems that seasonal relations and life-histories of animals are 

 comparable to habitat relations and habitat-preferences, w r hen 

 dealing with distribution in space. 



The growing season is not uniform in physical and vegetationa^ 

 features of the environment. Seasonal changes are conveniently 

 marked by changes in aspect of the vegetation. The successive 

 changes in the environment for grasshoppers in the course of a 

 season are somewhat different in forest associations from those in 

 grassland. 



A field of study of seven weeks is not long enough to determine 

 seasonal relations of grasshoppers, nor to determine what species 

 of grasshoppers occur in that region. Clwrtopliaga mrldifasciata 

 (De Geer), an early spring grasshopper almost certainly occurs 

 at Douglas Lake. Melanoplus scudderi (Uhler) and Melanoplus 

 punctulatus (Uhler) may reasonably be expected to occur within 

 the region. Both are short-winged forest-inhabiting species of 

 late summer and autumn. 



The time of adult activity of such species as were found, how- 

 ever, is known; the species may be arranged according to life- 

 history into the following groups: 



1. Species which hibernate as nymphs, appearing as adults in spring, remaining 



active only during early summer, represented by Hippiscus luberculatus. 



2. Species which hibernate as eggs, maturing very early in summer or late in 



spring, becoming scarce or disappearing by about September i. Melanoplus 

 minor, M. bivittatus (sometimes persisting in numbers till frost), M. fasciatus 

 (this species may more properly belong in the fourth group). 



