ENTOMOLOGY. 45 



CHAPTER III. 



" Let no presuming impious railer tax 

 Creative Wisdom, as if aught was formed 

 In vain, or not for admirable ends*" 



THOMSON. 



FKOM the flies, of infinite variety, which haunt 

 the water, the trout makes no invidious selection ; 

 all, as their successive genera spring into exist- 

 ence, in the wonderful economy of insect birth, 

 become its greedy and welcome prey. By far the 

 greater portion of those delicate and fragile crea- 

 tures those "emblems of human life, and beings 

 of a day" which form the food of trout, are 

 produced from Iarva3 which inhabit the water. 

 These are strictly aquatic flies. But not a few 

 species found upon the water are bred upon the 

 land, and are indebted to the wind, or some other 

 accidental cause, for their transition to another 

 element. Among these last are the cow-dung 

 fly, the hazel fly, the ant fly, and many other 

 well known species. 



The flies which are most commonly imitated 

 by "routine anglers" belong to two families of 



