EEV. A. E. EATON OX RECENT EPHEMERID.E OR MAYFLIES. 2G9 



black. Fore femur and base of tibia light yellowish greeu ; the remainder of the tibia 

 lighter in tint ; kinder femora and the bases of the tibiae whitish, with a yellowish green 

 tint ; the remainder of the tibite smoky white. Tarsi smoky white, or greyish, with 

 ])]ack joinings and ungues. Setae smoky white with rufescent joinings. IFheii dried the 

 wings are transparent dull light yellowish, and it depends upon what was the period at 

 which the specimen Avas killed whether the cross veinlets are also yellowish or else 

 brownish or black. 



Imago {dried). — Femora not dark-banded. Dorsum of the abdomen devoid of a longi- 

 tudinal median dark stripe, but with the terminal margins of the segments narrowly 

 dark-bordered nearly from side to side. Metathorax as pale at the sides as elsewhere. — 



d {living). Eyes at first ctesious, with a transverse dark line and movable markings 

 like those of the subimago : sometimes they are tinged with pale yellowish green above, 

 and more deeply so below. At a later period, and when viewed under artificial light, 

 their colour changes to black or greenish black ; but later still it is apt to become cajsious 

 again. Head and sides of the thorax marked as in subimago with either black, piceous, 

 or fuscous. Pronotum light greenish bistre, or olive-brown ; the remainder of the notum 

 either light pitch-browu or somewhat brown-ochreous : tegulse, pleurse, and sternum 

 much paler, and variously coloured with pale greenish yellow, pale greenish brown, &c. 

 Dorsum of abdomen in segments 1-7 or -8 (excepting at the sides) translucent light 

 greenish brown, or olivaceous grey, narrowly darker (often pitch-black) at the terminal 

 margins of the segments ; segments 8 or 9-10 opaque, and more or less brown-ochreous 

 varied with yellow ochre. Venter in segments 1-7 or -8, and the sides of the corre- 

 spending dorsal segments, very pale transparent olivaceous green ; the remaining ventral 

 segments opaque and somewhat yellow-ochreous. Seta3 smoke-grey, or greyish white, 

 with black, pitch-brown, or rufescent joinings. Fore legs subolivaceous, sometimes 

 tinged with yellowish brown : tarsus smoky grey ; the tip of the femur, both extremities 

 of the tibia, and the tarsal joinings, blackened. Hinder legs yellowish -green or whitish 

 amber-colour, with the tarsus and tij) of the tibia smoke-grey, and often with the tarsal 

 joinings blackened. "Wings vitreous, with pitch-black neuration, excepting that, towards 

 the roots, the principal nerviu-es arc often tinged with greenish- or amber-yellow : in the 

 fore wing the whole of the submarginal area and at least the pterostigmatic portion of 

 the marginal area are of a greenisli- or yellowish-amber tint, the pterostigmatic parts 

 being subopaque and often tinged with grey ; but frequently the remaining portion of 

 the marginal area is likewise amber-tinted. In dried specimens the greater portion of 

 the wing-neuration becomes pitch-brown ; the axillar fold of the fore wang is bordered 

 externally with a slight brownish cloud ; the legs to a large extent become strongly 

 amber-coloured, and the notum raw-umber brown ; while the thoracic pleurai often lose 

 the dark markings and become almost uniformly pale brownish yellow. 



2 {living). — Eyes either light yellowish green, glaucous, coisious, or black ; on each 

 side of the face and vertex at the orbit of the eye is respectively a triangular black spot 

 md a triangular fuscous spot. Notum laterally of the very lightest shade of brown-ochre, 



out along the middle fuscous, with the peaks of the meso- and metanota yellow-ochreous ; 



n front of the upper part of the base of the intermediate coxa is usually a fuscescent or 



