16 EPHEMERID^E OF OTHER RIVERS. 



a fly which is usually found on fast rocky rivers. The subimago 

 is large nearly as large as a May-fly ; it is of a general brown 

 colour and is easily recognised by the heavy brown blotches 

 upon its wings. 



The imago of either sex is known as the Great Red Spinner ; 

 the female is perhaps the brighter of the two, though there is 

 not much to choose between them. The wings are clear with 

 a suggestion of green about them and black neuration. The 

 thorax is pitch brown, changing to black with age. The 

 abdomen is a rich red brown. 



Counting the March Brown, there are altogether five species 

 of the genus Ecdyurus, and the next on the list is E.insignis, 

 w r hich differs from E.venosus in that it is appreciably smaller 

 and the light sepia grey wings are without the characteristic 

 brown blotches mentioned above, whilst the neuration is green- 

 grey with black cross- veinlets. The setae are black. 



The male 'spinner has a whitish green abdomen, the last 

 three segments being brown ochre. The wings are clear with 

 dull green neuration, cross veinlets black. The female spinner 

 is like the male except that the abdomen is light greenish olive 

 throughout. 



E.voUtans is recorded by Eaton as having been found on the 

 Riven Thames. The imagines of this species are sufficiently 

 like the Great Bed Spinners to be covered by this name. 



E.lateralis in the dun stage has wings of a blackish grey 

 much like the Blue-winged Olive, both in colour and size, but 

 sometimes there is more of a brown tinge about them. The 

 spinners both have a jet black thorax with a yellow streak in 

 it. The wings are clear with pitch brown neuration. The 

 abdomen is brown. This fly is, of course, smaller than the 

 March Brown. 



Next we come to the one instance in which the angler appears 

 to have got ahead of the scientist. The August Dun, some- 

 times known as the Autumn Dun, has no scientific name. It 

 undoubtedly belongs to the same genus as the March Brown, 



