I08 INSECT LIFE. 



of winged forms probably enables these insects to 

 spread overland from one pond or stream to another, 

 but the conditions under which winged forms occur 

 are not well understood. Sometimes a third form 

 occurs in which the adult has short wings. It should 

 be remembered that the nymphs of the winged forms 

 have short wing-pads, but these differ in appearance 

 from perfect wings. 



The Families of Water-striders {School Work). 

 — There are two closely related families of bugs the 

 members of either of which could well be called 

 water-striders on account of their mode of life. In one 

 family the legs are much longer than in the other, and 

 better fitted for the gliding motion characteristic of 

 water-striders ; the members of this family are termed 

 " the water-striders." In the other family the legs 

 are shorter and fitted for running rather than rowing; 

 as the body is broadest across the prothorax in 

 these insects, they are termed " the broad-shoul- 

 dered water-striders." 



Separate from the others those specimens of water- 

 striders in your collection in which the second and 

 third pairs of legs are extremely long and slender, 

 and in which the body is widest back of the pro- 

 thorax. If this family is well represented in your 

 locality, you should have some species in which the 

 body is long and slender, as in Fig. 88, and also some 

 smaller species in which the body is oval in outline. 



Copy the following label and fasten it above the 

 place where the water-striders are to be put in your 

 collection : — 



Order Hemiptera (He-mip'te-ra). 

 The Bugs. 



