PREFACE ix 



and they are no less distinct in their 

 varieties. It was natural to assume, 

 therefore, that the flies which would he 

 fitting lures at one time would not be 

 fitting/ at others; and that for the other 

 times there were appropriate flies, if only 

 one could find them. The arrangement 

 set forth in The Book of Flies is the 

 result of observations and experiments 

 which have at least been constant and 

 painstaking. 



The problem of the lake fiies, however, 

 was not com,pletely solved lohen the dis- 

 tribution into months had been settled. In 

 what sizes were the lures to be presented ? 

 Naturalists admit that the standard sizes 

 are as a rule larger than the real insects ; 

 yet, in spite of this, practically all anglers 

 use flies of the standard patterns. This 

 habit is not in accord with the assumption 

 set forth in the pages that are to follow, 

 which is that Nature is the true guide. 

 Nevertheless, excepting in the cases of the 

 Green Drake and the Stonefly, which are 

 life-size, the standards are adopted in The 



