240 EEV. A. E. EATON ON EECENT EPHEMERID.I: OR MAYFLIES. 



piceous or almost to brown-ochre, and commonly traversed by a darker longitudinal 

 median stripe in front. The ventral markings in segments 1-8 compose a continuous 

 median dark stripe dilated in the middle of each of the segments (although not always 

 distinctly so in some of the hinder segments) : the usual pale dots are indistinct or 

 absent. In dorsal segments 1-8 the terminal border is very distinctly edged with dark 

 colouring, which extends almost to the lower margin of the hinder lateral angle, and 

 which, in lieu of running forwards in a curve at the side of the segment, exhibits at most 

 only a short acute projection barely reaching the edge of the scar of the nymphal 

 tracheal branchia. (Livinff.) — d . Eyes roman sepia-brown. Notum either fusco-luteous, 

 or pitch-brown varied with pitch-black. Superficies of the dorsum light bistre, or 

 greenish grey ; the underlying tissues especially in segments 8-10 are often tinged in some 

 measure with orange or yellowish : at the terminal margin segments 1-8 are bordered 

 narrowly and somewhat evenly with piceous, and the bordering almost extends to the 

 lateral margins of the hinder angles of the pleuree in segments 1-7 ; but in segment 8 it 

 ceases at the pleurae so as to leave the hinder angles of the segment wholly of the 

 lighter colour ; in segment 9 a triangular streak of a similarly dark colour extends on 

 each side in proximity to the pleura from the terminal margin to the base of the segment. 

 Moreover in every abdominal segment the dorsal vessel is bordered on both sides with 

 light brownish, this colouring forming in segments 4-6 twin triangles, acuminate behind, 

 having the track of the vessel as their common base adjacent to their acute angles. 

 Venter light yellowish olive-grey, tinged in the penultimate segment with brown-ochre, 

 and traversed lengtliwise by an extremely light jecinoreous or burnt-umber stripe in 

 segments 1-7, which is dilated angulaidy in the middle of each segment so as to be 

 resolvable into a continuous series of hexagonal spots, broad in the anterior segments 

 and elongated in the hinder segments ; in each of these spots are the usual pair of pale 

 dots beyond the middle, and three longitudinal dark lines (the dark borders of the nerve- 

 trunks visible through the integument) in front. Forceps olivaceous or w^arm sepia- 

 brown, with the last two joints dusky inside. Setse warm sepia-brown, becoming more 

 intense towards the roots. Fore femur pitch-lu'own or rufo-piceous, the tibia and tarsus 

 darker, with the distal edges of the intermediate tarsal joints whitish : when dried the 

 femiir in opaque view becomes bistre-brown, with the lower edge dark for some distance 

 from the base, and with faint indications of a dark broadly diffused streak a little before 

 the middle ; the tibia and tarsus become pitch-brown or pitch-black ; in transmitted light 

 the femur becomes brownish amber-colour, the tibia more opaque tlian it, and the tarsus 

 subequal in translucency to the femur. Hinder femora pitch-brown, dark at the tips ; 

 tibia? dull reddish pitcli-brown ; tarsi black or pitch-black : when dried the femora in 

 opaque vieio become light bistre-brown, each dark at the tip and with a dark longitudinal 

 streak almost from the base nearly to the middle, tapering at both ends ; and the tibiae 

 and tarsi become pitch-brown. Wings vitreous, tinged with bistre-brown or sometimes 

 bistre-grey in the pterostigmatic region of the fore wing : neuration in opaque view 

 black, in transmitted light pitch-brown, excepting at the bases of the wings, where 

 the colouring of the main nervures becomes deficient or at most light raw-umber 

 brown. 



