EEV. A. E. EATON ON EECENT EPHEMEEIDJi OE MAYFLIES. 179 



black-brown.] Notum either fuscous or pitch black. Dorsal segments 1 and 7-10 of the 

 abdomen either deep chestnut-brown or pitch-brown ; segments 2-6 either translucent, 

 light sepia or Cologne-earth grey with the joinings dark, or else cretaceous ; venter m 

 segments 7-9 light Roman sejjia-brown. Seta? and forceps whitish. Legs translucent 

 whitish ; fore leg faintly tinted with brownish, varying with change of light to whitish 

 amber ; the femur with a well-defined pitch-brown band at the tip separated by a short 

 clear space from an ill-defined greyer band a little beyond the middle ; tibia brownish in 

 the vicinage of the distal articulation ; ungues in some lights brownish : hinder femora 

 banded with pitch-brown at the knee only, the adjoining part of the tibia brownish at 

 the articulation, the tarsal joinings and ungues also light pitch-brownish. Wings 

 vitreous : the great cross vein and the bases of the nervures included between it and the 

 thorax pitch-brown ; in the pterostigmatic portion of the marginal area of the fore wing 

 are 5 or 6 simple cross veinlets, and between them and the bulla are rudiments of 2 or 3. 

 Length of body 3-4 ; wing 4 '5 ; setae, 6 im. 7-8 mm. 



Sab. Holland, near Arnhem (Van Medenbach de Rooy, 8tli Sept.). I subsequently 

 met with it there, between the town and the railway bridge below the town on 26th July, 

 and at first mistook the species for Ba'etis niger, on account of its coloration and its 

 finger-like forceps-limbs. 



AMERICAN SPECIES. 



Centroptilum PoiiYi, sp. nov. 



Imago {dried), 6 . — Thorax above lutescenti-fuscous or pitch-brown ; abdominal 

 segments 2-6 transparent whitish ; the spiracles and tracheal trunks darker in individual 

 specimens ; segments 7-10 purple-sepia brown above, paler beneath ; seta? white, with 

 their joinings towards the base brownish. Wings vitreous ; the principal longitudinal 

 nervvires brownish near tlie wing-roots ; the costa, subcosta, and radius, very faintly brown 

 amber ; the terminal margin and finer nervures, in certain lights, brownish grey ; about 

 6 nearly straight and simple cross veinlets in the pterostigmatic space; interneural 

 veinlets of the terminal margin mostly in pairs. Legs whitish ; the fore femur throughout, 

 the hinder femora distally, slightly yellowish ; fore tibia and tarsus light sepia-grey, 

 hinder tarsi and ungues less distinctly so. Length of body 4, wing 4 mm. 



Eab. Rangel Mountains, Cuba (Poey & Ch. Wright) [Hag. Mus.]. The wings of a 

 carded snbimago are of a light sej^ia-grey. 



A small undescribed species of Centroptilum from Arizona (1 S im., 2 subim., in 

 M^Lach. Mus.) has likewise paired interneural veinlets along the greater part of the 

 terminal margin of the fore wing. 



CLOEON, Leach, 1815. 

 Illustrations. Adult (details) PL XVII. Zla-d ; (whole figures) see under C. diptermn, 

 citation of Stephens (1835) and iCloe] Pictet (1843-5). Nymph PI. XLVII. ; see also 

 under C. dipterum, citations of [Ephemera'] De Geer (1771), Goring and Pritchard (1829), 

 Bowerbank (1833), Blanchard (1840), of [Cloe'] Calori (1848), and of [Cloeopsis] Vayssiere 

 (1882) ; also under C. rufulum of iChloeon'] Lubbock (1863 & 1865). 



24* 



