24 AQUATIC INSECTS. 



extreme interest. It is difficult at times to furnish the necessary 

 food for the rapidly growing larvae and especially difficult to 

 provide suitable environment at time of pupation. However, the 

 difficulties to be overcome only add more inteiest to the problem. 



In conclusion a word may be said regarding the aquatic 

 Hymenoptera. Only a few species are known and they are 

 parasites eidier on the larvse of Caddis-flies or on the eggs of 

 various aquatic insects. The wonderful adaptations or modifi^ca- 

 tions of these tiny insects in order to enter the water and oviposit 

 in such out-of-the-way places are often remarkable. This offers 

 an inviting field to the interested nature-lover, and surely some 

 one will undertake ro discover and record such interesting 

 creatures. 



Aquatic insects are not only of wonderful variety and diversity 

 but are of great economic importance. They form a large per- 

 centage of the food of our fresh-water fishes. In order to study 

 the fish-food problem one should be familiar with aquatic organ- 

 isms, particularly insects. Could we control the breeding of 

 many of our aquatic insects we could immediately begin a water 

 culture similar to oar present day agriculture, with this difference, 

 that the crops would be, — fishes. In many places our fresh- 

 water fish supply is rapidly becoming depleted despite the millions 

 of young fry that are planted every year . These young fry are 

 distributed without any knowledge of the environment in w^hich 

 they are placed, so that millions die because of uncongenial sur- 

 roundings, and lack of suitable food supply, while many others 

 are devoured by predaceous forms. It is to be hopf d that in the 

 near future we may see started an extensive study of our immense 

 areas of fresh water in order that the basic principles of fish 

 culture may be determined. In the meantime whatever facts can 

 be gleaned by the study of aquatic insects will be of permanent 

 value . 



