96 THE EEPOET OF THE No. 36 



basis of a permanent food supply for fishes. Along with the rearing of the forms 

 suitable for fish food it will always be necessary to keep out of our ponds the 

 predaceous forms such as the larger species of Dytiscidae and Hydrophilidae. In 

 my limited observations on these forms I found them to attack small fish and kill 

 them very easily. So it will also be necessary to carefully study the predaceous 

 forms in order to lessen the dangers of fish culture. 



The basic food of our fresh waters is vegetable, largely plant plankton. This 

 forms the basis for the animal plancton which in turn provides the food supply for 

 the younger fishes. Our herbivorous insects in turn provide a considerable food 

 for larger fishes while these in turn are devoured by larger fishes. If we see to it 

 that the final product is a profitable crop of edible varieties of fish we will at least 

 have laid the foundation of a successful water culture. 



All of us are compelled to earn a living, and the economic problems at present 

 awaiting solution provide us with means for a livelihood. These problems are 

 mainly concerned with the growing of land crops. Surely the future will also 

 find us hard at work developing a successful water culture. In the meantime 

 anything which we can do by adding one life-history of an aquatic form or isolated 

 notes may be of use in the future, and will be of permanent value. 



De. Walker: I am very glad indeed that this subject has been brought up 

 again. I think that most of us who heard Prof. Needham's address at the Annual 

 Meeting two years ago realize, for the first time, the great possibilities offered by 

 our large tracts of swamp water in the artificial cultivation of aquatic insect larvae 

 as food for fish. Our fresh water fisheries are becoming rapidly exhausted, and 

 it is high time that more active steps were being taken to prevent any furtheir 

 depletion of these important natural resources. It is only by such careful in- 

 vestigations of the food of fish and the means by which it may be cultivated that 

 a sound basis for such work can be obtained. 



De. Hewitt: I should like to thank Dr. Matheson for his interesting 

 address and also to state thaJt there is really no necessity for him to 

 apologize, as he seemed to be doing, for bringing forward a paper which is of the 

 utmost economic importance. Dr. Matheson said that there is a great necessity 

 for our study of aquatic insects. It seems to me that the proper place for studies 

 of that kind is at the universities. Students who are looking for subjects for 

 research work are the ones to take up this kind of study, as we cannot at present 

 afford to devote our time to problems primarily involving a large amount of invest- 

 igation along lines not of an immediate economic nature. I regard that owing 

 to the fact that there are so few of us at present working on the economic aspects 

 of entomology we are in consequence so extremely busy with our own branches 

 of work. Therefore, I would suggest to Dr. "Walker and others in charge of re- 

 search at our universities and colleges that those students might devote their 

 time, that is, those with inclinations in these directions, to studies of this kind; 

 the students in universities and colleges are those in the best position at the 

 present time to carry on these investigations. We heard with great interest Dr. 

 Needham's address two years ago on this important subject. Dr. Matheson has 

 again called attention to the important relations of a study of aquatic insects to 

 the question of the conservation of our fresh-water fish supplies. I would suggest 

 that we take some definite action in this matter and that we move a resolution 

 calling the attention of such a body as the Commission of Conservation, who have 

 to deal with the conservation ,of our fresh water Ifishes, etc., to the necessity of 



