THE GREAT WATER-BEETLE 363 



and then pour water upon him, it runs off the polished surface 

 of his body just as it does from a duck's back. If we lay him 

 gently on the surface of the water, he will struggle hard to dive, 

 but will not succeed, because his shiny body repels the water. By 

 dropping from a height, however, as he does after a flight, the 



Great Water-Beetle and Grub 



impetus of his fall carries him beneath the surface; and then, of 

 course, he can swim and dive without difficulty. 



Sometimes, however, he makes a very curious error; for, mis- 

 taking the glass of a greenhouse for the surface of a pond, he 

 lets himself fall upon it. Water-beetles are often quite stunned 

 in this way, and are found in the morning in the gutters, or on the 

 ground below. 



The eyes of the great water-beetle are very large, and project 

 considerably from the head. Thus the insect is enabled to see in 



