CHAPTER XIV 



THE PLECOPTERA 



The most usual common name for the Plecoptera is the Stone-flies. 

 They range from small to good-sized insects whose bodies are quite long, 

 flattened and with rather parallel sides. The wings are nearly always 

 well developed and with many cross-veins, though in a few cases they are 

 very small and in some species the cross-veins are few. Considering 

 only the more usual condition, the fore wings extend well behind the 

 end of the body when closed and have a considerably smaller area than 

 the hind wings which are so broad that when they are at rest upon the 

 upper side of the body they must be folded lengthwise into plaits to 

 reduce them to the necessary width (Fig. 43). 



FIG. 43. Adult Plecopteran (Pteronarcys regalis 



Folsom.) 



Newm.). Slightly reduced. (From 



The antennae are long and composed of many segments. In most 

 members of the group a pair of cerci is present at the end of the abdomen. 

 The mouth parts are of the chewing type but are generally so weakly 

 developed as to be practically useless. The larvae live in water and do 

 not differ greatly in appearance from the adults. 



The group may be described as follows: 



Insects which as adults have four membranous wings, usually longer 

 than the body, and generally with many cross-veins. Hind wings larger 

 than the front ones and when at rest folded lengthwise and lying, covered by 

 the front pair, on the abdomen. Antenna long: a pair of caudal cerci 

 usually present: mouth parts for chewing but generally poorly developed. 

 Metamorphosis incomplete. 



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