1891.] A. E. Eaton — Notes on some native Ephemeridse. 409 



should be ranked as one of the Ephemera Type. The costel shoulder 

 of the hind wings is rounded ofE obtusely, just as in Rexagenia, but the 

 pronotum resembles that of a Pentagenia. Precise identification of the 

 genus is precluded by the ruinous condition of the specimen. 



Until now only three species of Ephemera have been described from 

 India, — E. immaculata, Etn., from Cuna, E. expectans, Walker, from 

 *' Hindostan," and E. supposita, Etn., from Ceylon. Of these the first 

 has no abdominal markings, but the others have linear dorsal and ven- 

 tral markings. Two other species of Indian Mayflies, also with linear 

 markings, have long been represented by single specimens in Mr. 

 McLachlan's cabinet ; and in the present collection there is sufficient 

 additional material for their description. They are nearly related to 

 E. supposita, which therefore may advantageously be treated of in this 

 paper, although wanting in the Calcutta Museum. 



Ephemera supposita, Eaton. 



Described from $ subimago in Baron E. de Selys-Longchamp's 

 Museum; 1 c? im. in McLach. Mus. ; compared with the ? subim. stand- 

 ing with the type-specimen of Potamanthus [ = Atolophlehia] fasciatus in 

 Hagen's collection, and with S specimens in the British Museum : cf. 

 Trans. Linn. Soc. London, 2nd Series, Zool. iii. 73, pi. viii. 12"^ (1883) or 

 [for pattern of dorsal markings] Trans. Ent. Soc. London, (1871) p. 75. 

 The following notes are supplementary to these earlier descriptions of 

 the I? imago. 



Neuration of the forewing distinct to the unaided eye when held 

 over white paper, with perhaps the exception of only the branchlets of 

 the intercalar veins annexed to the anal nervure ; over a dark back- 

 ground, when viewed under a lense facing the light, the radius and the 

 stronger parts of the subcosta of the forewing, and the cross veinlets in 

 both wings remain dark, but the other nervures become pale ; in trans- 

 mitted light the nervures assume an amber tint. Membrane of the fore- 

 wing (excepting the distinctly coloured parts) perfectly transparent in 

 direct view : but held obliquely at a moderate distance, fronting the 

 light, the finer of the longitudinal nervures transmit to it a faint yel- 

 lowish grey ; or pointing towards the light, the cross veinlets transmit 

 to it a faint reddish grey : in proximity to the cosfca, the pterostigmatic 

 portion of the marginal area is rather deficient in colour. I was prob- 

 ably mistaken in 1883 when I described the dorsal vessel as dark ; but 

 the ravages of cabinet pests preclude certitude on this point. 



The dorsal abdominal markings of the best marked segments com- 

 prise six black longitudinal stripes or streaks united to one another by 

 the burnt unaber brown apical border of the segments, — three on each 



