162 PEV. A. E. EATON ON RECENT EPHEIMEEID^ OE MAYFLIES. 



Cloeon rhodani, Walk., List of Neuropt. lus. in Brit. Mus. part iii. 573 (1853) ; Hag., Ent. An n 

 (1863) 31 ; !Etn., Ann. & Mag. of Nat. Hist. (3) xviii. 14.7 (1866). 



Buetis rhodani, !Etn., Trans. Ent. Soc. London (1871) 114, pi. v. 20, 20e [details]; Meyer-Diir, 

 Bull. Soc. Ent. Suisse, iv. 309 (1874) ; Rostock, Jahresb. d. Ver.f. Natiu-k. Zwickau, 1877, p. 86 (1878) ; 

 Palmen, Paar. Ausf. giluge d. Gescld. org. b. Insect. S. 64, 68, 71, taf. iii. 45 [anatom.] (1884). 



Subimago [living). — Wings eitlier cinereous or dark brownish grey, with greenish grey 

 neuration. Fore femur greenish grey, with a dark crescentic spot or an ill-defined light 

 grey spot before its distal extremity, the tibia light sepia-grey, the tarsus dull black ; 

 hinder femora light greenish- or yellowish-white, the tibiae greyish white, the tarsi dull 

 black ; setae greenish grey, with reddish or warm sepia-brown joinings. 



Imago {living). — d . Turbinate eyes intermediate in colour between deep sepia- and 

 madder-brown above, much lighter at the sides ; lower eyes deep sepia-brown. Thorax 

 jet-black above. Abdomen in large examples greyish bistre- or umber-brown in segments 

 2-6 or 7, with the joinings opaque ; the remaining segments of a richer umber- or bistre- 

 brown, with ochraceous joinings ; venter dark greenish grey, often with two short 

 divergent sepia-grey lines, each followed by a dot near the base of almost every segment. 

 Setge greenish grey, with sepia-brown or dull red joinings. Forceps greyish or greenish 

 grey, their third and fourth joints whitish, more or less. Femora light olive-green or 

 dark greenish grey ; tibiae and fore-tarsus light grey ; hinder tarsi light grey or black. 

 Wings vitreous, the nervures very faintly tinged with bistre-grey. 



Variation. — Small examples have segments 2-7 of the abdomen translucent light 

 greyish, each of these having the usual three dorsal linear marks in the middle of its 

 base and the spiracles faintly darker grey, and having the edge of the distal border of 

 the segment in the middle of the back, and also a spot in the midst of the dorsum on 

 each side, orange-fuscous. Legs greyish, the tibiae in some Mghts appearing whitish with 

 their tips dark grey, and the hinder tarsi dark grey. 



$ . Very similar to the male ; the abdomen opaque throughout. In specimens of 

 either sex that have only just cast the subimaginal slough, the thorax is visually pitch- 

 brown above; it becomes jet-black afterwards. Length of body 5 '5-9 ; wing 5'5-9 6 

 and -12 ? ; setae, 6 im. 13-19, subim. 105, $ im. 16 mm. 



Hub. Great Britain, in streams and rivers, ascending to upwards of 1000 ft. in Derby- 

 shire ; in the south this species is matured on sunny days in the depth of winter where the 

 water has an average temperature at that season of about 51° F. Widely distributed on 

 the Continent : the Vosges (M^Lach.) ; lowlands of Switzerland, e. g. Lake of Geneva 

 (1230 ft.), Tirol (Brauer) ; also Corsica (Bellier). Common in Madeira up to 3000 ft. 

 and in Gran Canaria, near Sta. Brigida and San Mateo up to about 4600 ft. The terminal 

 joint of each of the forceps-limbs is small and globular. 



Baetis Bocagii, sp. nov. Plate LXIV. 13 (forceps). 



Subimago {lining). — Wings tinted with griseous. 



Imago {living). — c? . Tiu-binate eyes dull light red ; lower eyes dark olivaceous. Thorax 

 jet-black above. Abdomen in segments 2-6 fusco-griseous, with the joinings of the 

 segments and an abbreviated longitudinal line from the base on each side of the median 



