28 THE UNIVERSITY SCIENCE BULLETIN. 
the result that the Corixids came to occupy the added forage 
grounds in this shallower water, for Corixids are lovers of shoal 
waters and adapt themselves in time to the oscillations of the 
pond in which they live. The species of boatmen studied pos- 
sessed no functional wings and must as a rule be bound to 
permanent water. But permanent water does not imply that 
the life within is not subject to varying fortunes and conditions 
as shown in the notes on Bool’s Backwater. For this pool 
would be threatened with unsightly patches of filamentous alge 
during extended dry hot weather, but be cleansed again with 
the next rains. And these factors enter into the life of the 
organisms within its waters. 
INTERRELATIONS WITHIN THE POOL. 
When one undertakes to study the adjustments of any one 
set of organisms to each other he finds the field restricted and 
unknown on every hand. He may pursue disturbing factors 
into other groups only to find these factors held in balance by 
still other causes, and so ad infinitum. -Not an organism of 
the pool can escape the influence of its fellows, and no final 
analysis can be reached till all are understood. 
The pool is indeed a restricted environment and yet only the 
more obvious facts are known concerning the life within it. 
In introducing, therefore, a few ecological notes relating to i 
the water bugs the writer has not the temerity to claim more 
than a designation of the more apparent features. These are 
considered briefly in the following outline: 
a. Haunts and Habits. 
b. Habitat Key. 
c. Relation to other organisms. 
1. Parasitism. 
2. Oviposition. 
3. Feeding habits. 
While the relation of the water bugs to other organisms is 
largely a question of feeding habits, it is well to consider first 
of all the relative location of each form. Haunts and habits 
determine in large measure the range of influence of each unit 
in the environment. 
In another chapter the families of water bugs are enumer- 
ated. There are thirteen of them. Four are limited in large 
measure to the moist shores adjacent to the water. Two live 
upon the rafts of alge and other vegetation floating out from 
a eee, 
