OF ARTS AND SCIENCES. 37 



can hope to understand the conditions of their larval stage. 

 Finally, we must know the life historj^ of the darter, from the 

 egg to the moment that it is seized by the trout. 



The horsefly larvae can serve as food for the darters during 

 onl}- a portion of the year, and probably a relatively small por- 

 tion. The trout may eat the darters all the 5^ear round, if the 

 latter are suflScientlj^ abundant ; but the darters themselves 

 must, at some period of the year, find other food than the larvae 

 of horseflies. We must know what this other food is, at what 

 time it is found in greatest abundance and where ; what condi- 

 tions are favorable or hostile to its development — in a word, be- 

 fore we can say intelligently and confidently that a given stream 

 or pond is properl}^ " stocked " with the necessary food supply, 

 and is, therefore, ready for the further " stocking " with trout 

 or other fish, we must know all the facts relative to all the life, 

 both animal and vegetable, in the water, on the shores, and in 

 the air above. 



Some of this work has already been done by those entomolo- 

 gists who have made a study of the structure and relationships 

 of certain groups of aquatic insects, but much more remains to 

 be accomplished before anj^one can speak with certainty upon 

 the subject of stocking even a single stream or pond. The State 

 of New York recently took a long step in the right direction. Un- 

 der the super^dsion of the State Entomologist, Dr. E. P. Felt, 

 an entomologic field station was established at Saranac Inn, in 

 the Adirondacks, in connection with the State fish hatchery 

 at that place. The station was placed in charge of Dr. James 

 G. Needham, Professor of Biologj^ at Lake Forest University, 

 whose report upon Aquatic Insects in the Adirondacks, issued 

 as Bulletin 47 of the New York State Museum, is by far the 

 most valuable contribution to our knowledge of this important 

 subject which has j^et appeared. 



But before Professor Needham's report came to hand, an un- 

 usual opportunity for the study of the return of plant and ani- 

 mal life to a body of water, rendered utterly barren of both by 

 mechanical means, was presented through the enterprise and 



4 



