CHAPTER XV. 

 PLECOPTERA. 



This is the order of the stone flies. In the same 

 water with the May flies, possibly, but where the water 

 runs swiftest, may be found some nymphs that look very 

 much like the May fly nymphs, but the bodies are flatter 

 and darker, and show some light and dark stripes. 

 These are the stone-fly nymphs, and they cling to the 

 under side of stones, whence their name. They cling 

 where the water current is swiftest, but when pursued, 

 they run very swiftly, and disappear under other stones 

 with amazing rapidity. '" 



The nymphs breathe by means of thoracic gills, one 

 tuft of filaments or one single filament to each leg. The 

 remains of these gills may be seen in the adults of some 

 species. The feet of the stone flies are provided with two 

 claws, while the May flies have but one. The larvas, 

 so far as they have been observed, are active and well 

 able to defend themselves. They are carnivorous as to 

 food habits, with strong biting mouth parts, the same as 

 the adults. The number of eggs laid by the females is enor- 

 mous, seeming to indicate that the larvae must take many 

 chances of being eaten ; and this is true. For, although 

 the nymphs are better able to protect themselves than the 

 May-fly nymphs, yet great numbers of them are eaten by 

 various enemies, fish, dragonfly nymphs, and water birds. 



The body of the adult stone fly is rather long and 

 flattish, and soft-walled. Its wings are membranous, 

 but the hind wings are larger than the front wings; and 



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