FIELD BOOK OF PONDS AND STREAMS 



Taeniopteryx nivalis. — Both the nymphs and adults are 

 slender, black or blackish-brown and the nymphs have no 

 gills (Fig. 152). These are winter stoneflies (PL I), the adults, 

 first emerging from the water and crawling over the snow in 

 February, but they are also commonly found through May. 

 Length one-half inch. Eastern and central states south to 

 North Carolina. 



Fig. 153. — Nymph and adult of AUocapnia 

 (Capnia) vernalis, an early spring stonefly. 



AUocapnia (Capnia) vernalis. — These are blackish stoneflies 

 usually less than half an inch long. Only one species, AUo- 

 capnia (Capnia) vernalis (Fig. 153), is found east of the Rocky 

 JMountains. The adults usually emerge from January to 

 April. Eastern and central states. Several species of the 

 very similar genus Capnella are found in northeastern North 

 America. 



Mayflies — Ephemerida {Plectoptera) 



Many persons have seen mayflies even though they have 

 not recognized them as such. They may have watched 

 g,Teat swarms of "flies" over a lake at twilight, or come upon 

 dead insects strewn upon the lake shore or beneath street- 

 lights, or have fished with the artificial bait-flies, many of 

 which are modeled after ma3^flies. 



198 



