2IO 



A qua tic Organisms 



The true bugs (order Hemiptera) are mainly terres- 

 trial, and have undergone on land their greatest differ- 

 entiation. The aquatic ones are usually found in still 

 waters and in the shelter of submerged vegetation. 

 Tho comparatively few in species, they are important 

 members of the predatory population of ponds and 



FIG. 117. A giant water bug (Benacus griseus) 

 clinging to a vertical surface under water, 

 natural size. 



pools. They are often present in great numbers, if 

 not in great variety. The giant water bugs (fig. 117) 

 are among the largest of aquatic insects. These are 

 widely known from their habit of flying to arc lights, 

 falling beneath them, and floundering about in the dust 

 of village streets. 



