168 EEV. A. E. EATON ON RECENT EPHEMERIDiE OE MAYFLIES. 



pars ii. 907 (1767) ; Fab., Syst. Ent. 304 (1775) ; [Sclisef., Icou. Jus. circa Eatisbon. inclig. ii. tab. cliv. 

 1, 2? (1776)]; Schr., Enum. Ins. Austr. indig. 305 (1781); Fab., Sp. Ins. i. 385 (1782); id., 

 Mant. Ins. i. 244 (1787); VilL, C. Lin. Ent. iii. 19 (1789); Gmel., Linn. Syst. Nat. eel. xiii. i. pars v. 

 2629(1790); Rossi, Fu. Etrusc. ii. 8 (1790); 01., Eucycl. Meth. vi. 419 (1791); Fab., Ent. Syst. 

 emend, iii. pars i. 70 (1793); Cederli., Fu. Ingricte Prodr. 135 (1798); Walck., Fn. Paris, ii. 9 (1802) ; 

 Panzer in Explic. Scbsef. Icon. cliv. (1804); Lat., Hist. Nat. Crust. & Ins. xiii. 98 (1805); Stewart, 

 Elem. Nat. Hist. Anim. K. ed. 2, ii. 225 (1817) ; Stepb., 111. Brit. Ent. vi. 67 (1835) ; Ronalds, Fly- 

 fish. Ent. ed. i. pi. ix. 16-17 (1836) ; Blancb., Hist. Nat. Ins. iii. 54 (1840). 



Cloel diptera, ! Ronalds, Fly-fish. Ent. ed. v. no. 16 (1856). 



Baetis niyer, ! Etn., Trans. Eut. Soc. London (1870) 6 ; ! id., op. cit. (1871) 119, pi. v. 26, 26a [detail]. 



Siibimaffo {living). — Wings black-grey. Legs of the $ dull greyish white ; 6 femora 

 very light yellowish green (prasinus) ; an abbreviated line or streak at the tip of the fore 

 femur dark, the tibiae and terminal joints of the tarsi greyish white, and the remainder 

 of the tarsi fawn-colour. Setaj of s grey, of $ cinereous. 



Imago {living). — d . Turbinate eyes reddish brown or light burnt-umber brown : lower 

 eyes olivaceous. Thorax jet-black above. Abdomen in segments 2-7 translucent, and 

 either white or light cinereous, with whitish or fuscescent joinings, and with the tracheal 

 trunks darker ; segments 8-10 either pitch-brown, reddish brown, or yellowish brown 

 above, and either whitish, greenish grey, or fuscous beneath ; nearly every ventral 

 segment has two short divergent dark lines at its base, each followed by a dot. Setae 

 white or greyish white, often with oj)aque joinings, or with some of the proximal joinings 

 faintly reddish. Eorceps with finger-Uke limbs, dark grey at the base and then light 

 greyish white. Fore femiir either light greyish white, or dull greenish white, or light 

 yellowish green ; the rest of the fore leg greyish, with the distal extremity of the tibia 

 reddish brown ; hinder femora white, slightly tinged distally with yellowish, greenish, 

 or grey ; the tibite dull whitish and the tarsi greyish white, or both of them of this latter 

 colour, with the distal edges of the tarsal joints black and the ungues piceous. Wings 

 transparent ; their neuration whitish pellucid, the subcosta and radius at the wing-roots 

 piceous. 



? . Eyes intense sepia. Dorsum of abdomen castaneo-piceous, with the terminal margins 

 of the segments, and often with three short streaks at the base of each of segments 2-6, 

 yellow ochreous : venter warm sepia, or burnt-umber brown, often with dark lateral L- 

 shaped marks. Setae either uniformly smoky or greyish white, or else greyish white 

 with rufescent joinings. Legs greenish testaceous, with the tarsal joinings dusky. 

 Length of body 5-7'5, wing 6-8 ; setae, d im. 9-11, subim. 9, ? im. 6-8'5, subim. 7 mm. 



Hab. Rivers in England ; May, June, and September. Also perhaps Sweden and 

 Courland (Brauer). The second nervure of the hind wing is usually forked, as in B. 

 pumilus. 



NOETH AMERICAN SPECIES. 



Baetis . 



t Cloeon X bioculata [exenpl. g], ! Walk., List of Neuropt. in Brit. Mus. part iii. 573 (1853). 



An undescribed species, 



Hab. St. Martin's Falls, Albany Kiver, Hudson's Bay (Brit. Mus ). 



