82 OUR INSECT FRIENDS AND FOES 



of the Beetle during this part of the work 

 being constantly immersed. On the 1 5th of July I 

 observed an opening at the foot of the mast, and 

 saw, floating round, whitish skins, either egg- 

 shells or the envelopes of the larvae. Next day 

 I saw a small larva emerge, and the day after fifty 



more." 



On making their escape from their silken 

 nursery the young mouse-coloured larvae set 

 forth in search of food. Strange to say, instead of 

 being chiefly vegetable feeders like their parents, 

 they are carnivorous in their diet, and are almost 

 as voracious as the larvae of Dytiscus, which they 

 somewhat resemble in appearance. Their bodies, 

 however, are thicker and more fleshy, and their 

 mandibles broader and toothed, while whether at 

 rest, or moving about at the bottom of the pond, 

 both head and tail are slightly turned upward, so 

 that the body always appears more or less curved. 

 From time to time they rise towards the surface 

 of the pond and stick their tails out to draw in 

 through the last pair of spiracles which open at 

 the tail, a fresh supply of air. The full-grown 

 larva is a large insect, of a dark sooty colour, with 

 the hard parts of both the head and the thorax of 

 a lustrous brown. When about to undergo 

 pupation the larva quits the^ater, and excavates 

 a little chamber in the mud. 



The Whirligig Beetles (Gyrinidce) have gained 

 their popular and scientific names from their 

 peculiar habit of moving swiftly in circles upon 

 the surface of the water. Throughout the 

 summer, their rapid gyrations may be witnessed 

 upon the surface of almost every pond or quiet 



