SOME AQUATIC INSECTS 83 



stream. They seem to love to sport together 

 in considerable companies; darting and circling 

 swiftly in all directions, and ever and anon 

 diving towards the bottom, and swimming 

 about beneath the surface; their downward 

 course through the water being easily observed 

 on account of the large bubble of air, glittering 

 like quicksilver, which they carry attached to 

 the extremity of the body. They are small, 

 blue-black coloured beetles, measuring about 

 a quarter of an inch in length. 



The Whirligigs pass the winter in a torpid 

 condition, buried in the mud amongst the roots 

 of the water plants. With the first warmth of 

 approaching spring, they awaken, quit their 

 winter quarters, and rising to the surface 

 of the water begin their merry dances, and 

 indulge in amatory embraces. As a result of 

 the mating of these beetles (that spent the 

 winter in a state of partial if not complete hyber- 

 nation), eggs are deposited, and a new genera- 

 tion of larvae are produced which grow rapidly 

 and, passing through their metamorphosis, 

 emerge as perfect beetles just as the summer 

 begins to wane, appearing in greatest numbers 

 during the latter part of August and the beginning 

 of September. 



The female Whirligig Beetle deposits her 

 elongated, oval-shaped eggs upon the sub- 

 merged leaves and stems of the water plants, 

 and from these eggs the curious centipede-like 

 larvae soon emerge. They are carnivorous in 

 their habits, their mandibles being pointed and 

 perforated by a slit through which they suck 



