201 



WATER BEETLES. 



(Plate 33.) 



We will consider three families — 

 I. Gyrinidae or ''whirligigs." 

 II. Dytiscidse or ''water tigers" or "diver 

 beetles." 

 III. Hydrophilidae or "lazy water beetles." 



I. Family Gyrinidae. This beetle (Plate 33, 

 Figs. 2 and 3) can be distinguished by the following 

 characteristics : (a) The habit of whirling on the 

 surface of the water; (b) It has two pairs of eyes, 

 an upper pair to watch for enemies in the air, and 

 an under pair to watch for enemies in the water 

 below. Thus they are sometimes called "daddy 

 four-eyes"; (c) The front legs are longer than 

 middle and back pairs and look like a pair of oars ; 

 the two pairs of back legs are broad, short and 

 paddle-like, alternately expanding and then col- 

 lapsing (Plate 33, Fig. 4); (d) The tip of the 

 abdomen is exposed; (e) antennae very short. 



Habits. Gyrinids or whirligigs can dive to get 

 I away from an enemy. They can also fly away to 

 other ponds. It is rather a surprise to find that 

 water beetles can fiy in the air, but the elytra 

 fit very tightly "round the body, and the spiracles 

 are under them. The wings are thus kept beau- 

 tifully dry. When they dive they have to tak^ 



