SYNOPSIS OF THE BRITISH EPHEMERID^. 27 



halves keep close together, is much expanded at the 

 tip, and almost T-shaped ; legs yellow ; tarsi brown ; 

 anterior legs dark brown ; wings hyaline, with brown 

 transverse veins ; costa pale yellow, with the apical 

 half brownish ; the apex of the marginal field with 

 oblique, irregular, partially double cells. 

 Female similar to the male ; the unicolorous abdomen 

 darker ; the costa of the wings paler ; ventral plate of 

 the last segment oval. 

 Length of the body $ 4^, $ 4| lines ; expansion of the 



wings $ lOJ, 2 llj lines J setas ^ 12, $ 7 lines. 

 Habitat England. 

 The description is made from English specimens. T have 

 not seen Pictet's type, but the identity appears probable. 

 Stephens' description of jB. elegans suits for this species : 

 perhaps it should be referred here. 



7. B. OBSCURA, Pictet? Ephem. 182, 9, tab. 23, fig. 1. 



Imago. Head and thorax shining-black; abdomen 

 brown, the tips of the segments darker 5 caudal fila- 

 ments dark fawn-colour, the joints annulated with 

 darker near the base ; anal forceps brown ; penis 

 divided (but not very perceptibly); legs brownish; 

 wings hyaline ; venation pale brown ; the apical part 

 of the marginal field with straight veins; costa very 

 pale yellowish. Female with the abdomen unico- 

 lorous pale brown. 



Length of the body $ 3i, 2 3i lines; expansion of the 

 wings (^ 9, $ 10| lines ; setee ^ 7, $ 6 fines. 



Habitat England, Ambleside. 

 The description is made from English specimens ; Pictet's 

 type I do not know. The B. ohscura of Stephens, which 



