POND LIFE. 



99 



The May- flies {Field Work). — Let us continue 

 our study of the insects that fly over ponds. In 

 many places, at certain periods of the year, the most 

 abundant of these are the May-flies. These are very 

 fragile insects with large, del- 

 icate fore wings, with the hind 

 wings much smaller or want- 

 ing, and with the abdomen 

 furnished at its caudal end 

 with either two or three many- 

 jointed, threadlike appendages 

 (Fig. 86). 



Although a few May-flies 

 can be found at almost any 

 time during the warmer parts 

 of the year, in each locality 

 there are certain periods dur- 

 ing which they are much more 

 abundant than at other times ; 

 then they are apt to appear in 

 great swarms. This period is 

 as likely to be in June or July as in May, despite the 

 common name of these insects. It is at such times 

 that a study should be made of their habits. If you 

 find that May-flies are abundant at any time and you 

 have not already made a study of them, it will be 

 worth while to postpone the study of any other in- 

 sects and devote your attention to these, for no other 

 insects described in these lessons have so short a pe- 

 riod of flight as the May-flies. While in the field 

 take notes on the following points : — 



I. The flight of these insects — contrast it with 

 that of dragon-flies. 



Fig. 86. 



