CHAPTER XXII 



Stone-flies, May-flies, Dragon-flies, Ant-lions, Scorpion- 

 flies, Caddis-flies 



Order PlecopTERA : Stone-flies. 

 (Gr. TrXeK-of = plaited, and 7rT6/oo'i' = wing.) 



A SMALL order, containing only one family, Perlida, closely 

 related to the Orthoptera. The larvae are aquatic, and 

 metamorphosis is " incomplete." 



The body is Orthoptera-like : all 3 thoracic segments 

 are distinct ; the abdomen is composed of 10 segments and 



Pro. 116.— Toiirg aquatic Ijarva of Pn-Jld, enlarged. 



usually ends in a pair of long, jointed cerci ; the antennae are 

 long, slender, and many-jointed : the hind wings are much 

 larger than the front wings, and fold like a fan ; but the front 

 wings are membranous, not stiff like those of Orthoptera. 

 When the wings are folded the front wings lie one above the 

 other, so that only one of them is seen. The mouth-narts 



