SPECIES OF BRITISH HYDROPHILUS. 



the British Coleoptera, as it measures, when arrived at 

 maturity, an inch and a half in length, while the superior 

 strength and courage manifested in its attacks on small 

 fish, and other animals larger than itself, is truly sur- 

 prising. 



About the latter end of April, and during the month of 

 May, small nests of these insects are often found floating 

 among weeds and water plants, in stagnant pools, and 

 are frequently taken in the nets of those who are search- 

 ing for the early kinds of larva?. They are in the form 

 of balls, of a dusky white colour, and a silky texture, and 

 have each a small stem of the same nature as the nest, 

 but more dense. By means of this filament they are 

 attached to the roots or stalks of weeds at the bottom of 

 the water. (See the right hand figure at the head of this 

 chapter.) In this situation they remain during the 

 winter, and are thus effectually preserved from the 

 effects of intense cold. Early in the spring, the stem or 

 cable to which we have referred is detached from the 

 weeds, 1^y the winds which at that time prevail, and the 

 nest rises to the surface of the water, and there floating, 

 receives the genial influence of the sun. These nests 

 may be taken and placed in a basin of water, and, as the 

 season advances, hatched by the heat of the sun. On the 

 larva leaving the nest, which it accomplishes by gnawing 

 a hole in the side, the infant immediately descends to the 

 bottom of the vessel, with its jaws extended in search of 

 prey, and eagerly devours all the small aquatic insects 

 that are within its reach ; if, however, there is a scarcity 



