The Ecology of a Sheltered Clay Bank 161 
the stage, the dominant members of the association cor- 
respond to the leading characters; the secondary species, 
always present, to the essential but subordinate charac- 
ters. The individual animals adjust themselves to one 
another, especially to the dominant forms, and to the 
environment, as the personalities in the play adjust them- 
selves to the dominant characters, to one another, and to 
the environment.. In both groups some individuals are 
dominant, some used and useful, some tolerated, others 
pick up the crumbs, still others are predatory or parasitic, 
and all must be mutually adjusted to one another and to 
the environment.’’”* 
How this classification of various types fits into what 
we here record, the reader may presently see for himself. 
(B) INTERRELATIONS OF ANIMAL LIFE. 
(a) Fauna of the unit. 
If all the bank’s a stage, and all the six and eight- 
legged creatures merely players, it is fitting that we 
should give now a cast of characters, in the order of their 
importance, and follow the careers of the dominant ones 
for the five years, 1917 to 1921. Early in the work it was 
seen that the many insects did not use the clay bank and 
the environs in the same way, but they were easily classi- 
fiable into four distinct groups. 
Group 1. Pioneers. The permanent dwellers in the 
clay bank and environs, in a general way the pioneers. 
Group 2. Renters. The insects less hardy and more 
ease-desiring than the pioneers; those which rented 
or appropriated the abandoned dwellings of the pioneers. 
They might be called squatters. 
*Guide to the Study of Ecology, p. 47. 1913. 
