EEV. A. E. EATON ON EECENT EPHEMEEID.E OR MAYFLIES. 129 



short and acute. Wings vitreous, the fore wings tinged slightly with light hrownish 

 grey in the pterostigmatic region of the marginal and submarginal areas ; neuration 

 piceous, strongly defined (excepting the cross veinlets in a large extent of the marginal 

 and submarginal areas, and those in a small portion of the next area of the fore wing), 

 the longitudinal nervures becoming lighter at the wing-roots. Fore legs in opaque view 

 pitch-brown, ligliter or more nearly raw-umber brown from the coxa to the base of the 

 femur ; in transmitted light the tibia and tarsus are less opaque than the femur, the 

 dark parts become rufo-piceous, and the lighter parts somewhat of an amber-colour. 

 Hinder femora similar in colour to the fore femur ; but the tibiae and tarsi are uniformly 

 whitish yellow-ochre, with the ultimate joints and ungues, or in some lights the whole 

 of the tarsus, clove-brown. Length of wing, ? 15-18 ; setse, ? im. 16-17, subiiu. 15 millim. 

 Hah. Colorado (M'^Lach. Mus.) ; The Geysers, Yellowstone, 4th of May (Mus. Comp. 

 Zool. Cambridge, Mass.). The arrangement of the colouring matter of the abdomen in 

 the specimen described above is not to be implicitly trusted. 



Ephemerella Walkeri (renamed). 



XBaetis\\fuscata,W\a\\s., List of Neuropt. Ins. in Brit. Mus. part iii. 570(1853) [part]: Hag., 

 Smithson. Miscell. Coll. (18G1), Syiiop. Neuropt. N. Am. 47. 



Imago, S {dried). — Thorax above dark pitch-brown, varied on the pleurae and sternum 

 with light burnt-umber brown. Abdomen discoloured, dark pitch-brown. " Fore legs 

 piceous " {teste Walk.) ; hinder femora dark rufo-piceous, the tibia? and tai'si dull pale 

 subtestaceous. Wings transparent, their longitudinal neuration in some lights pale 

 fuscescent. Length of wing 8 millim. 



Hal). St. Martin's Falls, Albany Iliver, Hudson's Bay (Dr. Barnston) ; one example 

 in Brit. Mus. The 6 subimago doubtfully referred to this species by Mr. F. Walker is 

 still in the collection, and is most probably a llhithrogena. The name given by Walker 

 to this species, having been preoccupied in Ba'etls, is superseded : had lie not published 

 a description of the type-specimen, it might Avell have remained nameless and uudescribed. 



Ephemerella invaria, AValker. Plate XIV. 24 c (penis). 



{ Ba'etis invaria, ! Walk., List of Neuropt. Ins. iu Brit. Mus. part iii. 568 (1853) ; Hag., Smithson. 

 Miscell. Coll. (18U1), Syuop. Neuropt. N. Am. 48. 



Ephemerella invaria, \ Etn., Ent. Mo. Mag. v. 87 (18G8) ; ! id., Trans. Eut. Soc. London (1871), 100, 

 pi. V. 8, 8 a [details] . 



Imago, d {dried). — Thorax above light rufo-piceous ; abdomen discoloured, — dorsum 

 fuscescent, the joinings opaque, the last two segments modified with light dull reddish 

 orange, — venter greyish, the base of the forceps, and the two or three segments imme- 

 diately preceding it, light brown ochre. Fore femur and tibia reddish golden brown, the 

 latter with a dull light reddish spot near its distal extremity, the tarsus yellowish wiiite ; 

 hinder femora translucent, very light straw-colour or pale yellowish-fuscescent, the tibise 

 and tarsi dull whitish, with the apical edges of the joints and the ungues fuscescent. 

 Wings transparent, their neuration usually colourless, but in one instance distinctly pale 

 fuscescent. Length of wing 8-10 millim. 



