4^2 



THE INSECT WORLD. 



l^accophuus minutus. 



Fig. 492. 

 Hydaticus grammicus. 



Fig. 493. 

 Pelobius Hernianni. 



The GyrinidcE, which come very near to the Dyticidce, like clear 

 water which is a little agitated. They are small black insects 

 (Figs. 494, 495), living in troops, and swim rapidly, describing 

 incessantly capricious circles, which has gained for them the name of 



w 



Fig. 494.— Gyrinus natator. Fig. 495.— Larva of Gyiiaus natalor. 



*' Whirligigs." They are remarkable for the disposition of their eyes, 

 which are double ; so that the Gyrinidce seem to have four eyes. The 

 lower ones look into the water and watch for the prey or the fish tliat 

 advances as an enemy ; whilst the upper eyes look upwards towards 

 the air, and warn the insect of the approach of enemies from abo\e. 

 To escape from fish^ the Gyrinus jumps out of the water, and also 



