NEUROPTERA. 



417 



ceiving food. The larvae have, at the end of their bodies, two long 

 threads, which remain in the perfect Perla, but not in the perfect 



Fig. 387. Perla bicaudata. 



Fig. 388. Nemoura variegata 



Fig. 389. Nemoura variegata (larva). 



Nemoura ; the latter lose the two caudal hairs when they arrive at 

 the adult state. One species of Perla is very common on the quays 

 of Paris. 



The Ephemerida, or May-Fly family, have long, slender bodies, 



