REPORT OF THE FOREST, FISH AXD GAME COMMISSION. 5OI 



be extended to include all living organisms, because it is not only necessary in such 

 a study to ascertain what any one species of fish, for example, feeds upon, but 

 u-e must also know what its competitors devour, and its relation to other fishes. 

 The mere knowledge of the species of insects found in association with any one 

 kind of fish, combined with some idea of their value as food, is only part of the 

 question, because, as in the case of the fish, we must know what each insect feeds 

 upon, and in turn its relations ro other insects inhabiting the same surroundings. 

 As these investigations are pushed farther and farther it may be found that all 

 living organisms, including even the lowest of the plants and animals, have some 

 bearing upon this question. The unraveling of the intricate relationships existing 

 in any such group is a labor of years, and the study must be undertaken with the 

 greatest care and discrimination ; otherwise, many incorrect conclusions may be 

 drawn. 



Before this investigation is completed it will make demands not only upon the 

 entomologist and the ichthyologist ; but the botanist and the zoologist, using the 

 latter term in a very general sense, will also be called upon to assist in solving 

 some of these interesting and practical problems. 



Intricacies of Insect Societies. This subject alone is one calling for considerable 

 study as will at once be seen by an examination of Plate i, which was prepared 

 and drawn under the direction of Dr. J. G. Needham. There we find depicted 

 in a portion of a running stream a number of interesting and diverse insects, and 

 when these are taken from their native habitat and carefully identified and reared to 

 maturity, we find that the apparently large number of forms represented above this 

 bit of rushing water is by no means excessive. Living side by side in the water, 

 there may be found not only the small Siiiiidiuin larv?E but the interesting nymphs 

 of two species of Mayflies, the young of a predaceous caddis fly and the aquatic larva 

 and pupa of a small fly. These insects obtain their living in some manner or other 

 from the rushing water or the things borne along by it, and the biologist who 

 attempts to solve the relationships existing between the forms, even in such a 

 limited colony as this, will find therein material for many months of study, and when 

 this investigation is pushed farther, to include not only a little colony in one limited 

 portion of a stream, but all of the aquatic insects or all of the forms living in a brook 

 or pond or lake, the amount of work necessary will be immensely increased. 



Insects as Fish Food. Some fish are dependent for sustenance upon insects and 

 other forms which spend a greater or less proportion of their lives under the water, 

 and certain species obtain a considerable part of their nourishment from insects 

 which live in the neighborhood of Avater and fall upon its surface only by accident. 



