ROSS: HOW TO COLLECT AND PRESERVE INSECTS 



35 



are stonefly adults that emerge in winter and are 

 active on bridges from November through March. 

 Figs. 25 and 26 illustrate Isoperla confusa Frison. 



Ephemeroptera 



Mayflies 



This order is one in which 

 the nymphs or young live in 

 streams and lakes; the adults 

 are terrestrial and are found along the edge of 

 the water from which they have emerged. The 

 nymphs are varied in shape and have short 

 antennae, long legs, which are often flat- 

 tened, and three tails at the end of the 

 body. The adult flies have very 

 long front legs, short antennae, 

 practically no mouthparts, 



Fig. 27. — Ephemer- 

 optera. Hexagenia lim- 

 bata, the adult form; 

 this mayfly is also 

 called shadfly or willow- 

 fly. These flies some- 

 times emerge in great 

 swarms and congregate 

 in piles around bridge 

 or city lights. Actual 

 length about 1.0 inch. 



Fig. 28. — Ephemer- 

 optera. Hexagenia lim- 

 bata, an abundant Illi- 

 nois mayfly that in the 

 nymphal stage pictured 

 here lives in water and 

 emerges when full 

 grown into the fly. Ac- 

 tual length about 1.0 

 inch. 



