EEV. A. E. EATON ON EECENT EPHEMEEID.E OE MAYFLIES. 187 



lines or stripes of the same colour upon the vertex • the facial carina has two small 

 piceous tubercles on each side. Abdomen luteo-fuscous or raw umber above, with the 

 terminal edges of the segments testaceous or very light brown-ochreous, and with dark 

 subcutaneous tracheae ; venter olivaceous, with the last two segments tinged somewhat 

 with straw-colour or light yellow-ochre. Legs olive-green, with darker tibige and tarsi. 

 Length of body 9-10 ; wing, c5' 8, ? 10-11 ; setae, 6 im. 14-15, subim. 9, ? im. 10-14, 

 suhim. 7-9 mm. 



Sab. Great Britain, in still water and in sluggish streamlets, during September and 

 October. France, Autun (M'Lach.). Portugal, at Almodovar, Alemtejo (600 ft., 7 May), 

 water 65° F. ; Sao Marcos da Serra (580 ft.) ; and Silvcs, Algarve (about 130 ft., 16 May). 

 Also in Switzerland at the Statzer-See, near St. Moritz in the Engadine (about 6000 feet, 

 16 August; M'^Lach.). The name obscurum was preoccupied in this genus by Curtis 

 [under C. diptermii]. 



Cloeon conciknum, sp. nov. 



Imago {living). — 6 . Turbinate eyes dull liglit yellow or chrome-lemon (JIavits) ; 

 lower eyes olive-grey. Notum raw sienna or furfuraceo-luteous. Abdomen in seg- 

 ments 6-10 concolorous above with the notum, with paler joinings ; segments 2-5 dirty 

 white, suffused with the same colour as the remainder, the main tracheae conspicuously 

 dark; venter in segments 8-10 somewhat ochraceous. Setae and forceps whitish ; the 

 limbs of the latter almost contiguous at the base. Hinder femora yellowish white ; 

 hinder tibiae and tarsi smoky white or whitish sepia-grey ; fore leg rather darker. Wings 

 vitreous. When dried the neuration acquires a faint dull amber tint in certain lights ; 

 the pterostigmatic region of the wing, likewise very faintly amber-tinted and of slightly 

 turbid trauslucidity, contains usually 11-13 rather irregular cross veinlets (of which a 

 few are forked towards the costa and some anastomose witli one another), seldom so small 

 a number as 7-9 (counted at the subcosta) : the fewer the cross veinlets, the more they 

 are branched and anastomose ; there are none before the bulla in either sex. 



$ (dried). — Very similar to the s . The cross veinlets of the pterostigmatic portion 

 of the marginal area, more regular in this sex, are usually 10-12, seldom 8 in number ; 

 and the membrane thereabouts is more transparent than in the d ; between the strictly 

 pterostigmatic region and the bulla are sometimes a few (about 4) indistinct rudiments 

 of cross veinlets. In dried examples of either sex the legs become more opaque than 

 those of living specimens ; femora sublutescent in opaque view, changing in transmitted 

 light to light yellowish-amber ; fore tibia and tarsus of 6 in some lights olive-grey ; 

 hinder tibiae whitish amber in transmitted light, nearly concolorous with the femora in 

 other lights ; hinder tarsi of 6 rather yellower than the tibiae, with the terminal joint 

 either brown-ochreous or olive-grey, and black ungues ; tarsi of ? often suffused with 

 green. Setaj dull whitish, with faintly opaque joinings ; in c? examples tlie setaj some- 

 times become faintly tinged with light brown-ochre. Length of body 7-5-8 ; wing 8-9 ; 

 setae, 6 im. 14-16, ? im. 11 mm. 



Sal). Portugal : the stream near Porcalhota, at the junction of the road from Mafra 

 with that between Lisbon and Cintra (480 ft., 1st June 1880, shortly before sunset, water' 



25* 



