THE DRAGON FLIES 73 



no food in the imago state; in fact their mouth parts are 

 so much reduced and atrophied that it would probably be 

 impossible for them to do so if they made the attempt. 

 The only function which the imago stage subserves is 

 that of reproduction. May flies frequently appear in 

 vast numbers in the vicinity of bodies of water and at 

 night they are often attracted to lights, under which the 

 dead accumulate in great heaps. Often the dead May 

 flies drop into the water and are washed ashore in masses 

 resembling large windrows. 



The caddis flies are much better known in their larval 

 than in their adult state. The larvae are remarkable for 

 surrounding themselves in a tubular case made of various 

 materials which they carry about with them. Some 

 species construct cases of sand, some employ irregular 

 sticks of wood, while a few make their cases of bits of 

 leaves which are cut out in a regular rectangular shape 

 and fastened together at the edges in a most neat 'and or- 

 derly manner. Usually only the anterior part of the body 

 is protruded from the case. The posterior part is soft 

 and generally furnished with outgrowths which serve 

 as gills, and at the tip of the abdomen there is a pair 

 of hooks by means of which the worm holds on to its case. 

 When the worms are removed from their cases they will 

 readily construct new ones if given the proper materials. 

 Caddis worms pass through a more or less quiescent or 

 pupa stage after the close of their larval life. The larva 

 closes up the end of its tube and transforms into a pupa, 

 which lies within the old case. The mature caddis 

 flies are somber colored, inconspicuous insects that are 

 usually not much in evidence. They frequent places 

 near the water in which they lay their eggs. 



The stone flies are similar in their habits to the May 

 flies. The nymphs generally live under stones in ponds 



