102 EEV. A E. EATON ON RECENT EPHEMEEID^ OR MAYFLIES. 



varied with slightly prominent rufescent markings. Abdomen discoloured, the venter 

 rather redder than the dorsum. Setee sepia-grey, annulated at the joinings with piceous, 

 the median seta lighter than the others ; the annulations of the outer setae towards the 

 roots, and again towards the tips, are subequal to one another in breadth, but many in 

 the intervening portion of the seta are alternately narrow and broad. Wings vitreous, 

 tinted very slightly throughout, and in the distal portions of the marginal and submar- 

 ginal areas of the fore wing rather more perceptibly, with light yellowish-brownish ; 

 neuration pitch-brown, changing to golden brown in transmitted light, but lighter in 

 colour in the parts corresponding with the paler regions of the subimago's wings. Fore 

 legs pitch-brown ; the hinder legs rather lighter and more nearly rufescent- or lutescent- 

 piceous in opaque view, changing in transmitted light to rufous; in some lights the 

 tarsi aj)pear browner than the tibite, and these, in their turn, lighter than the femora. 



Variety (from North Carolina). — "Wings of subimago more nearly uniformly sepia- 

 grey, and somewhat darker in tint than in normal specimens. Wings of imago clearer, 

 and in the s not tinged with brownish in the pterostigmatic region ; their neuration 

 lighter in colour. 



Length of body 9-11 ; wing 10-5-12 ; seta3, 6 im. about 30 & 7, subim. about 11 & 

 7 ; 2 im. 17 & 6, subim. about 13 & 7 mm. 



Sal). Cincinnati, Ohio (Say) ; Nova Scotia and (?) Newfoundland (Walker) ; Canada, 

 West Earms, N. Y., and Mt. Washington, N. H. (M''Lach. Mus.) ; Milford, N. H., Andover, 

 Me., and Morganton, N. C. (Hagen Mus.). The variation in colour of the N. C. examples 

 noted above may prove to be merely due to the advanced age of individual subimagines, 

 and premature death of imagines, respectively. 



Blastukus gravastelltjs, sp. nov. 



Subimago (dried). — Wings light grey, with dark neuration; the base of the hind wing 

 and the axillaiy region of the fore wing very little paler than the remainder of the 

 membrane, althovigh the main nervures are rather pale towards the roots. 



Imago [dried). — Median seta of d about ^ as long as the outer seta?; that of $ about 

 § or f as long as the outer. Pterostigmatic portion of the fore wing very faintly obscured 

 in 6 ; the marginal area in 6 contains 7-9 cross veinlets before the bulla and 19-22 

 beyond it, in $ 9-11 before and 19-24 beyond the l}ulla ; those in the pterostigmatic 

 space are slightly curved, and often branch irregularly in parts so as to anastomose with 

 one another near the costa. 



6 . Very similar to B. cupidiis ; pleurae and sternum varied in a lesser degree witli 

 rufo-piceous ; dorsum of abdomen more uniformly pitch-brown ; venter less brightly 

 coloured, segments 7 and 8 unicolorous, segment 9 not at all strongly contrasted in 

 colour with those preceding it ; forceps unicolorous, light testaceous ; setae sepia-grey, 

 annulated with piceous at the joinings, the annulations narrower and less unequal in 

 breadth than those of B. ctipidus 2 . Fore legs in opaque view uniformly pitch-brown ; 

 hinder legs luteo-piceous, changing in transmitted light to golden brown or rich amber, 

 with the extreme edges of their tarsal joinings faintly darker. Fore wings vitreous; 



