EEV. A. E. EATON ON EECENT EPHEMEEID.E OR MAYFLIES. 75 



Imago (dried), 6 . — Head above very light Mars-yellow oclireous, in 2 pitcli-brown. 

 Pronotum light raw-umber brown, with a linear pitch-brown longitudinal stripe on each 

 side ; the remainder of the notum in d slightly yellower, in ? brown-ochreous, varied in 

 the metanotum with light yellow-ochre. Abdomen above in d , and after oviposition in 

 $ , very pale translucent raw -umber, the hinder segments (7- or 8-9 or 8-10) light ycUow- 

 ochraceous, the tenth sometimes very light broAvn-ochre ; segments 2-9, each with a pair 

 of warm sepia-brown dorsal stripes, divergent and gradually tapering froin behind 

 forwards, descending obliquely one on each side from the hinder border to the spiracular 

 border close to the l)ase of the segment, and approximated to one another at the 

 hinder border more closely in the more forward than in the hinder segments ; these 

 stripes in segments 'i-8 are connected each with the other by an extension of the 

 saiue colouring along the intervening portion of the hind margin ; and the bands thus 

 connecting them together are intersected in the d , l)ut not in the S , by a tine longitudinal 

 black line along the dorsal vessel in segments G- or 7-0 ; this line in the ? does not 

 attain the hinder borders of the segments. Venter rather lighter than the dorsum in 

 segments 1-7, and thence posteriorly becoming bright l)rown-ochreous ; a fine pitch- 

 black streak on each side of segments 7-2, subcontinuous with the dorsal stripe of 

 the following segment, runs from the hinder angle of the segment obliquely inwards to 

 the anterior margin, subparallel with the immediately superjacent dorsal stripe ; viewed 

 laterally, the ventral streak of one segment in combination with the dorsal stripe of the 

 following segment appears slightly sinuous ; in segment 8 of the d the corresponding 

 ventral streaks taper at both ends, and do not reach the hinder lateral angles ; those in 

 the same segment of the ? meet one another close to the opening of the oviducts ; in 

 segment 9 they are subparallel with one another, almost perpendicular to the hinder 

 border of the segment, linear in the 2 , l)ut in the d broader, deep burnt-umber brown, 

 and sometimes ill-defined posteriorly. Setse deep warm sepia-brown, the joinings pitch- 

 black. Forceps light brown-ochreous, darker distallj^. Eore femur (as an opaque 

 object) light reddish brown, or (in transmitted light) bistre-amber colour, the tibiai 

 pitch-brown, the tarsus rather lighter ; hinder legs extremely liglit yellowisli ochre with 

 brownish ungnes ; the femora in transmitted light very pale yellow amber-colour. Things 

 vitreous, faintly tinted with light greenish yellow ; submarginal area of the fore wing 

 more strongly so tinted ; terminal margin of the fore wing very narrowly and faintly, 

 that of the hind wing more distinctly and to a moderate deptli, bordered with warm sepia- 

 grey ; neuration pitch-brown, the subcosta, or subcosta and radius, of the fore wing pitch- 

 black, the nervures becoming lighter towards the wing-roots, the bulla of the suljcosta 

 and that of the first sector, together with a minute spot, nearly in a line with them, on the 

 cubitus of the fore wing slightly greyish. Length of body, 2 , Il-IG, wing 18-19, 

 setse, ? im. 25-5, subim. 16 mm. 



Eab. Yokohama (Pryer, M^Lach. Mus.). 



PENTAGENIA, Walsh, 1863. 



Illustrations. Adult. PL VIII. 13 (details). 



Adult.— Yionoium in 2 transverse, enlarged posteriorly, subtumescent above, broader 



