64 SALMONIA. 



these flies on stagnant waters and lakes, 

 which form a part of the food of various fishes, 

 principally of the carp kind: but the true fish- 

 erman's flies those which are imitated in 

 our art principally belong to the northern, or 

 at least temperate part of Europe, and I believe 

 are nowhere more abundant than in England. 

 It appears to me, that since I have been a 

 fisherman, which is now the best part of half 

 a century, I have observed, in some rivers 

 where I have been accustomed to fish habit- 

 ually, a diminution of the numbers of flies. 

 There were always some seasons in which the 

 temperature was favourable to a quantity of 

 fly ; for instance, fine warm days in spring for 

 the grannam, or brown fly ; and like days in 

 May and June for the alder-fly, May-fly, and 

 stone-fly ; but I should say that within these 

 last twenty years I have observed a general 

 diminution of the spring and autumnal flies, 

 except in those rivers which are fed from 

 sources that run from chalk, and which are 

 perennial, such as the Wandle, and the 

 Hampshire and Buckinghamshire rivers ; in 

 these streams the temperature is more uni- 



