244 THE DRY-FLY MAN'S HANDBOOK 



traversing the faceted surface horizontally ; but when 

 it is deeper the upper part of the oculus (always much 

 the larger of the two), assumes a short subcylindrical 

 or turbinate form, faceted only on its summit, and 

 supports on its outer base the smaller division, which 

 is oval and faceted all over." 



Another distinctive mark of a male of any of 

 the Ephemeridse is the presence of a pair of forceps 

 or claspers on the lower side of the body at the hinder 

 end of it. These turbinate eyes and abdominal for- 

 ceps are not present in the females. The forceps are 

 generally referred to by modern entomologists because 

 the variations in their form, etc., are largely used in 

 determining the species when the insects are very 

 similar. 



The differences in the arrangement of the ner- 



vures of the hind wings are 



Hind wings of olive. most valuable indications of 



species. I will therefore, in 



the cases of the three insects — olive, pale watery, 



jPjg and iron - blue — give 



figures showing their 



hind wings magnified 



to such an extent as to 



be easily distinguish- 



^ 3° able. Fig. 43 shows 



one of the hind wings of an olive x 30. 



The fisherman will not have any great difficulty in 

 recognizing the spinners of the olive and other duns. 

 The glossy transparent wings and the absence of the 



