62 SALMONIA. 



Poiet. — Are water flies found on all 

 rivers ? 



Hal. — This is a question which I find it 

 impossible to answer; yet from my own ex- 

 perience I should suppose, that in all the 

 habitable parts of the Globe certain water 

 flies exist wherever there is running water. 

 Even in the most ardent temperature, gnats 

 and musquitoes are found, which lay their 

 congeries of eggs on the water, which, when 

 hatched, become first worms, afterwards 

 small shrimp-like aurelia, and lastly flies. 

 There are a great number of the largest 

 species of these flies on stagnant waters and 

 lakes, which form a part of the food of va- 

 rious fishes, principally of the carp kind: 

 but the true fisherman'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 habitually, a dimi- 



