EEV. A. E. EATON ON EECENT EPHEMEEID.E OE MAYFLIES. 165 



cai'cely darker, or else narrowly black. Wings vitreous ; neuration either pellucid 

 vhitish, or fuscescent [perhaps according to the age of the specimen]. 



2 . Very similar. Length of body 6-8, wing 7-8"5, setje, c? im. 14-16 mm. 

 Hab. England. Rills and streamlets on Ashbourne Green, Derbyshire, in June. Also 

 it Woolbridge, Ringwood, Hants, in September. Distinguishable from J5. rhodani 

 )y the minute dilatation or denticulation inside the extremity of the second joint of each 

 orceps-limb, and the distinctness of the tubercle similarly situated in the first joint. 



Baetis melanonyx, Pictet. Plate LXIV. 17 (forceps). 



CloS melanonyx, Pict., Hist. Nat. Nevropt. ii. Epliem. 258, pi. xl. 6 (1843-5). 

 Cloeon melanonyx, Walk., List of Neuropt. Ins. in Brit. Mus. part iii. 574 (1853). 

 Baetis finithnus, ! Etn., Trans. Ent. Soc. London (1871) 113, pi. v. 18, 18 a [detail]. — B. melanonyx, 

 d., op. cit. (1871) 118 [after Pict.]. 



Suhimago {living) $ . — Wings smoky grey, with dull greenish grey or suffuscous neu- 

 ation. Setae dark smoky grey, with rubiginose joinings. Eore femur and tibia greenish 

 jrey, varied with black at the knee, and with a dark cloud near the extremity of the former ; 

 arsus dark grey, with black joinings and ungues. Hinder femora smoky cretaceous, 

 vith a faint nebulosity before the extremity ; tibiae smoky grey ; tarsus dusky, with the 

 oinings and the lesser of the ungues black. Oculi olivaceous, with a movable black spot. 



Imago {living). — 6 . Turbinate eyes chocolate-brown on the summit, and narrowly so at 

 he base of the light yellow pedicel; lower eyes dull subolivaceous. Notu.m jet-black. 

 Abdomen fuscous above, darker or more opaque at the tips of segments 2-6, and through- 

 )ut segments 7-10 ; venter somewhat griseous in segments 2-6, lighter in segments 7-9, 

 )ale ochraceous in segment 10 and inside the basal joints of the forceps; the remainder 

 )f the forceps blackish basewards, but lighter distally. Sette somewhat greyish, with 

 larker joLoings near the roots. Fore femur olive-grey, the tibia and tarsus dull blackish 

 jrey; hinder legs rather lighter, with the tarsal joinings narrowly black; coxne olive- 

 jrey. Wings vitreous, with metallic gramineous (= medium green oxide of chromium) 

 md light carmine reflections ; pterostigmatic space of the fore wing slightly smoky or 

 aibopaque ; neuration translucent, the finer uervures in some lights subpiceous, the 

 stronger tinged with olive-grey. 



$ . Eyes subpiceous. Thorax dull black, or pitch-black, with paler sutures ; tegulse 

 ailphur-yellow. Abdomen either fuscous or pitch-black above, with the first three 

 loinings conspicuously pale, the next three piceous, and the others rufo-piceous ; venter 

 either dark bistre-grey with pale joinings, or greyish, with the last two segments often 

 somewhat ochraceous, traversed lengthwise by a pale median line, and having a dark 

 rounded spot at the base on each side of that line in every dark segment. Sette dusky, 

 nith darker joinings. Eore femur olivaceous : hinder femora light greenish grey ; tibiae 

 and tarsi in some lights dusky, with black joinings ; in other lights those of the fore leg 

 appear pitch-black, and those of the hinder legs pitch-brown ; wings vitreous, with the 

 greater part of the neuration pitch-black; subcosta and radius olive-grey. Length of 

 body, 6 5-7, 2 8-5-9, wing, d 6-7, 2 8-5-11 ; seta3, <S im. 12-18, ? 13-18 mm. 



Hah. A common alpine species in N. Italy, Savoy, and Switzerland : in the ueighbom-- 



