54 ANIMAL LIFE AND SOCIAL GROWTH 



it is necessary to include the distance covered by 

 all the symbols in order to find the value of the 

 most abundant form which is represented by the 

 outer part of the line. Thus in winter and spring 

 a few true bugs of the family Miridae, more leaf 

 hoppers and still more snails were to be found, 

 but in late summer the leaf hoppers were fewest 

 in number and the mirid bugs were most numerous. 

 All these forms were present throughout the year, 

 although they varied in numbers, and from time 

 to time assumed different degrees of relative 

 importance. Similar fluctuations of the impor- 

 tant vertebrates are not recorded. 



The outer circle represents the animals that 

 were strongly influential for more or less limited 

 seasons of the year. The scale of importance 

 here reads from the base line except for a few 

 inter-seasonal records. These seasonal animals 

 approach or surpass the permanent residents in 

 degree of influence during the period of their 

 greatest activity, but have practically no influence 

 at other seasons. From this chart it can be seen 

 that the whole community may be regarded as 

 being made up of a series of seasonal subdivisions 

 of which, in the present instance, six can be rec- 

 ognized; those of winter, late winter and early 

 spring, late spring, early summer, late summer, 

 and autumn. In other communities there may 



