CHAPTER VII. 

 Order PLECOPTERA (Ple-cop'te-ra). 



The Stone-flies. 



The members of this order have four membranous wings, 

 with comparatively few or -with many cross-veins ; the hind 

 wings are much larger tJian t lie fore wings, and are folded in 

 plaits and lie upon the abdomen when at rest. The mouth- 

 parts are of the biting type of structure, but are freque?itly 

 poorly developed. The metamorphosis is incomplete. 



The name of this order is from two Greek words : plecos, 

 plaited ; and pterou, a wing. It refers to the way in which 

 the hind wings are folded when at rest. 



Although the mouth-parts are of the biting type of struc- 

 ture, the mandibles are often small, flat, and membranous, 

 and evidently of little use. It is probable that as a rule 

 the adults eat but little. The antennae are long, tapering, 

 and many-jointed ; and in most species the caudal end 

 of the abdomen is furnished with two many-jointed bristles. 

 The nymphs are aquatic. 



This order includes only a single family. 



Family PERLIM? (Per'li dse). 



The Stone-flies. 



Those boys fond of fishing know that a ^ood place to 



find bait is under stones in streams. And doubtless they 



have often observed that in the swiftest portion of the stream 



the turned-over stones have clinging to the lower surface 



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