210 



ELEMENTARY ZOOLOGY 



(fig. 78) that bore into fruits, nuts and grains, and the 

 many wood-boring beetles, destructive to fruit-trees as 

 well as to shade- and forest-trees. 



The predaceous water-beetles (Dyticus sp. ) are common 

 in ponds and quiet pools in streams. When at rest they 

 hang head downward with the tip of the abdomen just 

 projecting from the water. Air is taken under the tips of 



FIG. 7v Moths of the peach-tree borer, Sanninoidea exitiosa, natural size; 

 the upper one and the one at the right are females. (Photograph by 

 M. V. Slingerland.) 



the folded wing-covers (elytra) and accumulates so that 

 it can be breathed while the beetle swims and feeds under 

 water. When the air becomes impure the beetle rises to 

 the surface, forces it out, and accumulates a fresh supply. 

 The beetles are very voracious, feeding on other insects, 

 and even on small fish. The eggs are laid promiscuously in 

 the water, and the elongate spindle-form larvae (fig. 77) 



