AQUATIC INSECTS. 21 



may be well to restrict it to a hurried discussion of the more im- 

 portant aquatic insects, and at the same? time direct the attention 

 of the members of the association to an inviting field at their own 

 doors. Assuredly no more interesting facts can be gleaned than 

 by studying aquatic organisms. All sorts of j)roblems will soon 

 ai)pear, and the solving of any one of them will abundantly repay 

 all efforts expended. 



The Maj'-flies (Ephemerida) are probably one of tbe most in- 

 terestin>; irroups of insects. From earliest times they have been 

 under observation and the May-fly dance has been the subject of 

 many interesting papers May flies are not particularly abundant 

 in species though very numerous in individuals One can easily be 

 convinced of this fact by observing the enoimous numbers of 

 nymphs that may be found in a single stream or observing the cast 

 nymjilial skins along the banks of rivers or ponds. Also when the 

 adults emerge they often appear nlmost as thick assnowflakes. The 

 nymphs occur in a variety of situations. Some are found burrowing 

 in the mud and ooze of ponds or streams, others in swift-flowing 

 water, in rapids or in gently flowing streams or in stagnant ponds. 

 In collecting for the nymph- one shoiild examine every possible 

 situation, for new facts may be gleaned at almost every turn. 



This i^roup is of very considerable importance, for both the 

 nymphs and adults furnish excellent flsh food. As they occur in 

 such large numbers thej'^ form a considerable part of the food of 

 certain fishes. Long ago Swammerdam observed that at the 

 time of emergence of certain May-flies the fish were larger and 

 fatter than at any other season of the year. If we had only some 

 successful method of rearing these forms the problem of a food- 

 supply in fish culture would be brought a long way toward solu- 

 tion. May-flies have long been used as bait for fishing and no 

 anglers' guide but gives an extensive account of the different 

 kinds suitable for alluring tbe hidden beauties. 



Stoneflies (Plecoptera) are a small, comi^act groui), widely dis- 

 tributed and very common in our clear streams. If one examines 

 the under side of any stone in our clear sparkling springs he will 

 be almost sure to find one or more of them rushing to the side 

 farthest from the light. They appear like shrimps and are very 

 active. The tip of the abdomen ends in two long setae while 

 nearly all the May-flies possess three anal filaments, The adults 



