290 REV. A. E. EATON ON EECENT EPHEMERID^ OE MAYFLIES. 



with black at the sides ; the first and the last of the stripes are less distinct than the 

 others. Pore femur intense olive-brown, darker towards the tip and at the edges ; tibia 

 blackish grey ; tarsus black. Hinder legs light greenish or olive-grey, with black tarsi. 



Imago {liclug), 6 . — Eyes at first either intense sepia-brown, intersected below by a 

 transverse sulphureous line ; or else warm sepia, divided by a light greenish line ; in 

 moribund aged specimens they often become csesious. {Dried) [dark specimens], — 

 Notum rufo-piceous or dark reddish brown ; a piceous or black stripe extends from the 

 tegulae to tlie fore coxa. Dorsum of abdomen broadly red-pvirple-brown along the middle, 

 with the tract of the dorsal vessel and a considerable portion of the hinder part of each 

 of the intermediate segments slightly darker ; in segments 2-8 the sides of the dorsum 

 are light yellowish ochre, intersected obliquely by reddish-purple stripes, extending in 

 each segment from the pale stigmata or s))iracles to the hind margin, and emitting a 

 short streak from the spiracle along the main trachea to the nymphal tracheal scar of 

 the jireceding segment; hence the sides of the abdomen may be described as striped 

 alternately with reddish purple and light yellowish ochre, the latter colour occupying 

 the hinder angles of the dorsum, and a sj)ace on each side of the base above the dark 

 stripes in each of the segments specified. The dark stripes referred to are gradually 

 dilated posteriorly from in front, and their width varies somewhat with the individual ; 

 whence the light spaces above the stripes at the bases of the segments vary also in 

 form, being in some specimens ovate or triangular spots, but in others very narrow 

 streaks. The hinder segments are more largely occupied by the dark colouring ; but the 

 tenth is almost wholly reddish purple. Venter spotless, either light yellowish ochre in 

 segments 1-G and in the forceps-basis, but tinged with reddish purple in the remaining 

 segments ; or else tinged more or less with reddish purple throughout. Setae whitish, 

 tinged with sepia near the roots ; the joinings piceous, and only for a short distance 

 near the base alternately narrow and broader. Eore femur and tibia pitch-brown ; tarsus 

 very light bistre-brow^u. Hinder legs light yellowish-amber, with the ungues and part of 

 the teriniual joint of the tarsus intense se2iia-l)rown, and with some brownish discoloration 

 close to the knee. Wings vitreous, almost imperceptibly tinged with bistre-grey in the 

 marginal and submarginal areas of the fore wing ; the pterostigmatic space is as clear as 

 the rest of the area ; neuration in most lights pitch-black or black, with the costa, sub- 

 costa, and radius of the fore wing pitch- or bistre-brown ; the great cross vein in most 

 positions remains black. Pterostigmatic cross-veinlets branched and anastomosing. 



Variation [light specimens {dried)], 6 . — Notum rich brown-ochre. Dorsum of 

 abdomen to a large extent in segments 2-6 or 7 translucent pale bistre-brown, inclining 

 to olive-brow'n, with the joinings also to a large extent slightly opaque. The sides of 

 the dorsum are rather paler than tlie midst, but are not strongly contrasted in colour 

 with it ; the lateral stripes are black, and do not reach the hind margins of the segments 

 in all specimens, but only in some. Hence the sides of the dorsum do not appear to be 

 striped alternately with a light and a dark colour, but only display dark stripes on a light 

 ground. Pore femur bistre-brown, darker towards the knee. 



$ {dried). — E-ather similar to 6 , but the notum is lighter. Fore leg bistre-brown, 

 dark at the tip of the femur : in many positions the tibia and tarsus appear as dark as the 



& 



