THE MARCH BROWN 



A CORRECTION BY THE AUTHOR 



Trout-fishermen for many generations have 

 been puzzled by the appearance on the river of 

 the March Brown during the summer and autumn 

 months. They have considered, surely with 

 reason, that the presence of a fly whose name is 

 associated with the month of March, should be 

 confined, more or less, to the early part of the 

 year. 



It was only in the spring of 1931 that an 

 explanation was forthcoming. The fisherman's 

 name, March Brown, covers two distinct flies 

 which are not only different species but belong to 

 different genera. 



The true March Brown has now been found to 

 be Rhithrogena haarupi, a fly described by Dr. P. 

 Esben-Petersen in Denmark in 1909 and, until 

 1932, unrecorded in the list of British Ephemeridae. 



It occurs in vast numbers during late March, 

 April and sometimes early May, on many of our 

 rivers, more particularly the Tweed. 



This fly, for more than three-quarters of a 

 century, has been confused, by fishermen and 

 entomologists alike, with another insect, Ecdyurus 

 venosus. The mistake originated in a faulty 

 determination in the fifth edition of Ronalds's 

 Fly-Fishers' Entomology. " Piscator ", the 



