EEV. A. E. EATON OX EECENT EPHEMEEID.E OE MAYFLIES. 225 



1873, p. 118 (1874) ; id., Proc. Ent. Soc. London (1874), p. vi; id. Journ. Linn. Soc. Zool. xii. L39- 

 146, pi. V. l-u^r (1874). 



Sitbimago {dried). — Wings, in opaque view, light sepia-grey ; neuratiou generally 

 piceous, but the principal nervuves become pale basewards ; the cross veinlets situated 

 in the portions of the fore wing bounded posteriorly by the inner and terminal margins, 

 and in front by the outer half of the sector (4) and the inner half of the pobrachial (7) 

 nervures, and all of the cross veinlets iu tlie hind wing are narrowly edged with faint 

 nebulous dark bordering ; those in the anterior portion of the fore wing (with the 

 exception of those in the extremity of the pterostigmatic space) are edged more or less 

 broadly with piceous — most broadly so in the marginal, submarginal, and the next 

 adjoining areas, — and their bordering in the basal halves of the first two areas is confluent 

 to a variable extent ; between the great cross vein and the last-mentioned cross veinlets 

 the membrane is pale, contrasting conspicuously with the adjacent parts ; aud in proximity 

 to the wing-roots the base of the fore wing from the radius (3) to the inner margin is 

 somewhat pale, both membrane and nervures ; and so again to a small extent is the mem- 

 brane in proximity to the bifurcation of the praebrachial (6) nervure. Setse dull pale 

 yellowish. 



Imago {dried). — $ . Notum dark pitch-brown. Abdomen of a duller colour than the 

 notum on the dorsum, but nearly as dark, probably discoloured considerably in drying ; 

 in segments 2-G the trachese appear to be pale and the joinings of the segments dark; 

 the sides of every segment in proximity to the pleurae are more or less dark ; segments 

 6-9 are traversed lengthwise l>y a fine median black line, and are marked eacli by a pair 

 of elongated dark spots or short streaks, one on each side of the line, at the l)ase ; the 

 pleural expansions of these segments, and in 9 and 8 a forked longitudinal streak just 

 above them on each side, are also dark. Venter light yellowish brown, with black or 

 piceous markings : the markings comprise in each of segments 2-7 a large l)lotcli on 

 each side, gradually rounded off towards the base of the segment, intersected by the pale 

 descending tracheoe near its anterior termination, and leaving only the joining pale ; also 

 a transverse streak at the joining, taiiering to a point from the middle in both directions, 

 whence is produced a short pointed streak or triangular citsp pointing forwards in the 

 middle of the hind border of the segment ; also a pair of small dots or oval spots, one on 

 each side of the middle of the segment aud in proximity to the point of the cusp ; also 

 the ventral ganglion nearer the base of the segment in the median line ; and, lastly, 

 another pair of larger oval spots set obliquely, and rather wider apart than the smaller 

 spots, one on each side of the middle near the base of the segment ; in segment 8 the 

 smaller pair of dots is extremely small, and in 9 they appear to be totally absent, the 

 larger pair alone remaining. Sette whitisii yellow, sometimes discoloured at the base. 

 Wings vitreous, faintly tinted with light brownish [excepting sometimes towards the tips 

 of the fore wings, perhaps in consequence of their having been seized between finger and 

 thumb at the time of capture] ; neuration piceous ; cross veinlets dark-edged, nearly in 

 correspondence with their edging in the subimago. Legs in 02)aque view dull light 

 brown-ochreous, all with the base of the femur, a broad baud before its extremity, one at 

 the base of the tibia, one embracing the tip of the tibia and the basal half of the first 



SECOND SERIES. — ZOOLOGY, VOL. III. - 30 



