Stoneflies 



203 



The sto7ie flies (order Plecoptera) are all aquatic. 

 They live in rapid streams, and on the wave- washed 

 rocky shores of lakes. They are among the most 

 generalized of winged insects. The adults are flat- 

 bodied inconspicuous creatures of secretive habits. 



Little is seen of 

 them by day, 

 and less by 

 night, except 

 when some bril- 

 liant light by the 

 waterside at- 

 tracts them to 

 flutter around it . 

 The colors are 

 obscure, being 

 predomin a n 1 1 y 

 black, brow^n or 

 gray; but the 

 diurnally- active 

 foliage inhabit- 

 ing chloroperlas 

 are pale green. 

 They take wing 

 awkwardly and 

 fly rather slowly, 

 and may often 

 be caught in the 

 unaided hand. 

 They are readil}^ 

 picked up with 

 the fingers when at rest. The wings (sometimes 

 aborted) are folded flat upon the back. They are 

 rather irregularly traversed w^ith heavy veins. The 

 tarsi are three-jointed. This, together with the flat- 

 tened head, bare skin, and long forwardly-directed 



Fig. 1 10. An adult stonefly, Perla immarginata. 



