214 How to obtain it. 



formidable claws, with which, if they once get hold, they seldom 

 relinquish their prey until they are satiated. 



By way of experiment, six alevin trout were placed in a small 

 tank along with two caddis worms, six with two large beetles, and 

 six with two sticklebacks. The experiment was repeated several 

 times with the same result ; the caddis worms killed more alevins 

 in a given time than either of the others. Again, a tank was 

 stocked with a mixed collection of insects, larvae, small fish, etc., 

 and the conclusion arrived at was, that the large caddis worms are 

 the most destructive of all. The large beetle larvae (Dyticus) is a 

 good second. They each settled minnows and sticklebacks, by 

 gripping them from below. The caddis worms seem to be more 

 active and more persistent in the chase, and their cases afford 

 inconspicuous covers, constructed as they are from bits of their 

 natural surroundings. The moral of this is that it is unwise to 

 have any but very small specimens in fry ponds. 



The May flies, or Ephemera, with which anglers are so 

 familiar, and which seem in some localities to be steadily decreasing 



in numbers almost annually, spend 



three years in the larval form in water. 

 The perfect insects may be readily 

 distinguished by their long tails and 

 vertically folding gauzy wings. The 

 larvae live in burrows in the muddy 

 parts of the river bank, under water, 

 and it is quite possible that this habit 

 of burrowing may account for their 

 extermination, by the increasing pol- 

 lution of some streams. The very 

 lengthened sojourn of these insects in * ^jJumefwuigaris*' 

 the larval stage greatly tends to reduce 



their importance to fish culturists. This is no reason, however, 

 for not planting them in districts where they have not hitherto 

 occurred, and to which it may be deemed expedient that they 

 should be introduced. 



The stone flies, the alder fly, the yellow Sally, the Spanish 

 needle, the willow fly, and the gauze wing, are all well-known 

 friends of the angler. They lay enormous quantities of eggs, 



