190 SALMONIA. 



dragon-flies are never found. There is no 

 difficulty in explaining why salmon in inland 

 rivers should take flies, where natural flies are 

 abundant; but fish, when they have lain long 

 in pools in the river and fed on natural flies, 

 will no longer take these bright flies, and 

 then even a trout-fly is often most successful. 

 I have sometimes thought that the rising of 

 salmon and sea trout at these bright flies, as 

 soon as they come from the sea into rivers, 

 might depend upon a sort of imperfect me- 

 mory of their early food and habits ; for flies 

 form a great part of the food of the salmon 

 fry, which, for a month or two after they 

 are hatched, feed like young trouts and in 

 March and April the spring flies are their 

 principal nourishment. In going back to 

 fresh water, they may perhaps have their 

 habits of feeding recalled to them, and na- 

 turally search for their food at the surface. 



POIET. This appears to me very probable. 

 But it is late, and we must return and com- 

 pare the crimped trout and salmon ; and I hope 

 we shall have another good day to-morrow, 

 for the clouds are red in the west. 



