212 How to obtain it, 



larval stage it is not so often seen, but will be readily identified 

 by the accompanying illustration. As will be seen, it is segmented, 

 and when fully-grown may be one and a half inches long, and is 

 provided with a most cruel pair of jaws, resembling pincers in 

 general form. It is not a particularly quick swimmer, but hunts 

 from ambush, amongst the sub-aquatic plants, and is one of the 

 most destructive insects we have in our fish ponds. 



The perfect insect or beetle is an inch or more in length, and 

 appears brown or purplish according to the lights, with a con- 

 spicuous yellow marginal line. The under side is reddish brown. 

 The only safe place for an individual of this species is among 

 mature trout, which quickly and unceremoniously attend its funeral. 

 As it leaves the water at will, and flies about in the air, and is 

 nocturnal in its habits, we never know exactly where we have it, 

 and it may come any night into our fry ponds. When, therefore, 

 part of the torn body of a little trout is discovered some morning, 

 it is time to keep a sharp look out for the enemy. These creatures 

 sometimes account for a good many fish. We hear of cases in 

 which trout fry in nursery ponds lessen in numbers unaccountably. 

 The Dytiscits may be, and often is, the culprit. 



Fig. 29. Hydropkilns picens and larva. 



Another insect belonging to the order Cohopcera, and to the 

 ordinary observer something like Dytiscus, is the Hydrophilns. It 

 is rather longer, and is more pointed "fore and aft," and is 

 harmless, being a vegetarian in diet, but it is not prolific, and is, 

 therefore, of no great apparent importance to the fish culturist, so 

 far as we know at present. 



There is another beetle which must be mentioned in passing, 



