SYNOPSIS OF THE BRITISH EPHEMERID^. 25 



description, is represented in the figure. The description 

 of B. lomjicauda, Stephens, suits very well, the length of 

 the caudal filaments indicates the male ; B. suhfusca of 

 Stephens indicates a smaller and darker female. Of B. cas- 

 ta lis, according to my observations, the female only belongs 

 to B. longicauda. 



This species comes very close to the preceding in form 

 and colouring. 



Probably B. mellea, Curtis, Phil. Mag. 121, 5, should 

 be referred here as the sub-imago. But M'here the allied 

 3ub-imago B. straminea, Curtis, 121, 5 a, should be referred, 

 I cannot say. 



4. B. ELEGANS, Stephens, 64, 6, S sub-imago, 2 imago; 

 Curtis, Phil. Mag. 120, 6. 

 The female in my collection, which, after a comparison 

 of the types I had labelled B. elegans, I am not now able 

 to separate from B. lutea. But as, according to my notes, 

 B. elegans is a distinct species, I can only here quote the 

 description of Stephens. 



" Bright ochreous-yellow ; abdomen palish-chesnut ; 

 filaments pale, the tips of the joints fuscous ; legs very 

 pale ochreous ; the tarsi with the apex of each joint 

 blackish; wings iridescent, pale ochreous-yellow; 

 costa darker, especially towards the apex, forming a 

 stigraoid spot." 

 Length of the body 4J lines ; expansion of the wings 



13| lines ; setse 8 lines. 

 Habitat near London. 



Probably B.jlavescensy Curtis, Phil. Mag. 121, 8, should 

 be referred here as the sub-imago. 



