Stoncfli 



es 



20' 



TJic stoneflies (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 fiat- 



hodied inconspicuous creatures of 



secretive habits. 

 Little is seen of 

 them by day, 

 and less 1 j y 

 night, except 

 when some bril- 

 hant light by the 

 waterside at- 

 tracts them to 

 flutter around it . 

 The colors are 

 obscure, l:»eing 

 predomin a n 1 1 y 

 black, brown 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 readily 

 picked up with 

 the fingers when at rest. The wings (sometimes 

 aborted) are folded fiat upon the back. They are 

 rather irregularly traversed with heavy veins. The 

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

 tened head, bare skin, and long forwardly-directed 



Fig. I lo. An adult stonefly, Perla immarginata. 



