THE BIG FLY. 163 



tributaries, and in a good many of the rivers which 

 .hold a large stock of coarse fish. They are also 

 caught now and then in trout streams proper, even 

 a mountain stream whose fish barely reach an 

 average size of three ounces occasionally yielding 

 -an overgrown monster of two or three pounds. 

 There is a difference, however, between such 

 a trout and a cannibal from a coarse-fish river. 

 The first is usually long, dark, big-headed, and 

 generally dyspeptic looking, whereas the other is 

 .shapely, bright, and in perfect condition. The 

 typical Thames trout, for example, cannot be 

 surpassed in looks by any of its brethren, and the 

 fish of the Colne and lower Kennet are equally 

 admirable. 



The explanation is simple. The mountain fish 

 has outgrown its food supply, and has to depend 

 chiefly on catching samlets or its younger relations, 

 which are agile enough to make this difficult ; the 

 Thames trout, on the other hand, has unlimited food 

 always at hand in the shape of bleak, small dace, 

 gudgeon, minnows, and other little fish which can 

 be easily caught. Somewhat akin to these big river 

 trout are those that inhabit certain lakes and 

 reservoirs and sometimes attain an equally large 

 size. As in rivers, their growth depends on the 



food supply, and it varies immensely in sheets of 



M 2 



