284 REV. A. B. EATON ON EECENT EFIIEMEEID^ OE MAYFLIES. 



XBaetls dispar, Curt., Load. & Edinb. Phil. Mag. ser. 3 (1831) 120; id., Brit. Ent. xi. 484 (1834) ; 

 ! Steph., 111. Brit. Eut. vi. 63 (1835).— 5. venosa, id., op. cit., I. c. ; Burm., Handb. d. Eut., Bd. ii. Abth. 

 ii. 801 (1839) ; Walk., List of Neuropt. Ins. in Brit. Mus. part iii. 556 (1853) ; Pictet, Hist. Nat. d. 

 Ins. Nevropt. ii. Epheui. 167 [part.] (184.3-5) ; Brauer, Neuropt. Austr. 26 (1857) ; Hag., Eut. Ann. 

 (1863) 22; Karsch, Die Insectenwelt, v. 400-2 (1863).— 5. .wS/MSca, 1 Steph., 111. Brit. Ent. vi. 64 

 (1835); Pict., Hist. Nat. Nevropt. ii. Epliem. 194 (1843-45) ; Walk., List &c. part iii. 561 (1853).— 

 B. purpitt-ascens, Pict., Hist. Nat. Nevropt. ii. Ephem. 174, pi. xx. 4 (1843-5) ; Walk., List &c. part iii. 

 557 (1853); Brauer, Neuropt. Austr. 26 (1857); Ausser., Ann. d. Soc. Natur. Modena, An. iv. 135 

 (1869) ; [??] Mocsary, Rev. d. Inhaltes der Termeszetrajze, Fuzetek ii. 124-5, or [German text] Naturh. 

 Hefte ii. Bd. ii. u. iii. 181-2 (1878) ?— 5. J longicauda, ! Ronalds, Fly-fisher's Ent. ed. 5, pi. ix. (1856).— 

 B. Xmontana, Hag., Ent. Ann. (1863) 26 [part]. — B. Picteti, Meyer-DUr, Mitth. schw. ent. Ges. i. 

 121 (1864). 



Ecdym-m venosus, !Etn., Trans. Ent. Soc. London (1868) 142 note [misspelt Ecdyonurus] ; lid., Ent. 

 Mo. Mag. xviii. 25 [nymph] (1881). — E. quce.^itor, \ id. MS., in the writing of PI. XXIV. 466 [penis] 

 (1883). 



Heptagenia venosa, ! Etn., Ent. Mo. Mag. v. 90 (1868) ; id.. Trans. Ent. Soc. Loud. (1871) 151 [part] 

 pl. vi. 24 [genitalia] ; Hag., op. cit. (1873) 404-5 ; ! Meyer-Dur, Bull. Soc. Ent. Suisse, iv. 314 (1874); 

 Rostock, Jahresb. d. Ver. f. Naturk. Zwickau, 1877, p. 92 (1878) ; Palmen, Paar. Ausf.-Giinge d. Geschl. 

 Org. b. Insect. SS. 40, 44, 47-48, 51, 65-6, 69, 70, 74, 76-80 & 92, taf. iv. 57, 59, 68, & taf. v. 93 [anatom.] 

 (1884). — H. niyrimana, Etn., Trans. Ent. Soc. London (1871) 144? — H. % lomjicauda, ! id., op. cit. (1871) 

 152, pl. vi. 25 [genitalia].— iy. Picteti, id., op. cit. (1871) 153. — H.purpurascens, ! Meyer-DUr, Bull. Soc. 

 Ent. Suisse, iv. 135 (1874). 



Subimago {living). — Wing-membrane either very light ivoi'y-black-grey, or very light 

 fawn or Cologne-earth grey, with the borders of the cross veiulets narrowly darker. 

 Before the moult, dark transverse stripes and bands appear ia the wings, similar to 

 those described under Heptagenia sidphurea. A greenish-yellow tint usually pervades 

 the pterostigmatic space, and is sometimes diffused about tlie base of the fore wing. 

 Fore femur piceous or olive-grey ; hinder femora olivaceous ; tibisje grey or l)lack-grey ; 

 tarsi black. Setae pitch-black. [Dried.) — The wings vary in appearance according to 

 the period at which the specimen is killed, as follows : — 1st, wings uniformly light sepia- 

 grey, with the cross-veinlets and most of the longitudinal nervures {i. e. all but the 

 stronger nervures) rather a darker grey, and equal to each other in definition ; 2nd, the 

 cross-veinlets become bordered with grey, and hence the longitudinal neuration becomes 

 less obvious to the naked eye ; 3rd, the colouring-matter of the wing-membrane appears 

 to become concentrated in the immediate neighbourhood of the cross-veinlets, so as to 

 produce dark transverse bands, leaving the spaces where cross-veiulets are scarce paler 

 than the other parts. The wings of some specimens might be described as of a dark 

 colour with pale transverse stripes and bands, instead of vice versa, light with dark 

 markings. 



Imago {dried). — Notum of d pitch-brown, sometimes approaching pitch-black; that 

 of $ lighter, sometimes brown-ochre or ferruginous brown. Fore leg of 6 uniformly 

 pitch-brown, excepting that sometimes the femur is lighter jvtst at the base ; 1st tarsal 

 joint of normal length. Pterostigmatic space usually more or less obscured, sometimes 

 clear. Terminal margins of the intermediate al)dominal segments dark, excepting at the 

 pleurae; dorsal segments 2-S marked, on both sides, either with a dark triangle, or 



