EEV. A. E. EATON ON EECEXT EPHEMEEIDiE OE MAYFLIES. 57 



bordered narrowly with blackish. Hind wing with similarly pale longitudinal and dark 

 transverse neuration, and with nearly all the cross veinlets bordered with blackish ; the 

 terminal margin not perceptibly bordered with colour darker than that of the disk. 

 (Texas.) 



Variation. — In the fore wing the dark borders to the cross veinlets are obsolete, and 

 those in the hind wing are much reduced in width. Both wings are quite free from all 

 tint of discoloration in the disk ; the marginal and submargiual areas of the fore wing 

 are greenish grey or light umber-grey ; the terminal margin of the hind wing not 

 bordered with dark colouring. (AVashington, D. C.) 



Variation. — Both wings are tinted alike throughout in the disk ; the marginal and 

 submargiual areas of the fore wing are tinted with umber-brown ; the hind wings are 

 bordered with black-grey along the terminal margin : the edgings of the cross veinlets, 

 mostly linear in the hind wing, are obsolete in the disk of the fore wing, but between 

 the great cross vein and the pterostigmatic region of this wing exist as a small rounded 

 spot on every cross veiulet, the roundness of the spots diminishing towards the ptero- 

 stigma. (Utah Lake.) 



Variation. — ^Wing membrane faintly and uniformly tinted in both wings ; no dark 

 bordering along the terminal margin of the hind wing ; no bordering perceptible along 

 the cross veinlets of the marginal and sultmarginal areas, next to none along those in 

 the disk of the fore wing, and hardly any along those of the hind wing. (New England.) 

 Variation. — Very similar to the foregoing ; but some faint indications (as spots) of 

 bordering in the marginal and submarginal areas of the fore wing, narrow sharply 

 defined edging to the other usually bordered cross veinlets, and a grey-black bordering 

 along the terminal margin of the hind wing. Hind legs in their general colouring duller 

 than usual. (Detroit, Mich.) 



$ imago (dried). — Integument of pronotum translucent very light bistre-grey overlying 

 yellowisii-ochre ; the rest of the notum, ranging in colour from dark yellow-ochre or duU 

 Italian-ochre to light brown-ochre, is varied with Boman-sepia at the projecting peaks ; 

 the light Roman-sepia streak extending backwards on each side of the notum from the 

 occiput is broadest at the hinder part of the pronotum, is much narrowed in front, and 

 is not clearly traceable (though sometimes faintly indicated) on the mesonotum. Dorsum 

 of the abdomen marked longitudinally with a median sepia or warm-sepia stripe, extending 

 from the first segment to very nearly the hind margin of the tenth : in segments 1-5 this 

 stripe is dilated posteriorly so as to form an acutely triangular blotch in each of them ; 

 in segment 6 the corresponding triangle is more slender and truncate ; in segments 7-9 

 the stripe in each segment maintains more nearly an evenness of width ; but it tapers to 

 a point behind in segment 10. Erom the median stripe in every segment but the last, 

 on each side of the dorsum, in the vicinage of the hinder border, a tapering streak of a 

 like colour extends obliquely forwards and downwards, either diagonally (as in segments 

 1-6) or (as in the longer segments 7-9) towards the spiracular border, gradually further 

 and further away from the anterior angle of the dorsum in successive segments. Venter 

 traversed lengthwise, or at least in segments 8 and 9, by a median linear stripe similar 

 in colour to the dorsal markings. Setee very light yellowish ochraceous. Pore femur 



SECOND SERIES. — ZOOLOGY, VOL. III. 8 



