XXIV 



WATER-BOATMEN AND BACK-SWIMMERS 



Among the many inhabitants of our streams, 

 ponds, and even ditches, none are more skilful 

 oarsmen than the water-boatmen. Their bodies 

 are perfectly adapted to their mode of locomotion. 

 Flat-backed, boat-shaped, and fitted with broad, 

 paddle-like legs, they dart through the water like 

 fragments of silver light. The bright sheen with 

 which they are clothed is said to be a thin layer 

 of air, taken from above the water in their not 

 infrequent visits thither and utilized by the insect 

 while below. 



Of the three pairs of legs possessed by the 

 common water-boatmen of our creeks, the hind 

 ones only are oar-like in form. These are broader 

 and flatter than the others and fringed with hairs. 

 When spread in the water these fringes aid mate- 

 rially in propelling the body forward. The middle 

 legs are very slender and are evidently little used 

 in swimming. The forward pair are small and of 

 great use in clinging to water plants, a favorite 

 pastime with water-boatmen, and in holding the 

 prey. 



This insect has a near relative whose acquaint- 

 ance is even more delightful than that of the small 

 and rather retiring boatmen. The back-swimmer 

 is a bold fellow, impatient and pugnacious, and 



(127) 



