EEV. A. E. EATON ON EECENT EPHEMEEID^ OR MAYFLIES. 97 



Leptophlebia vaciva, sp. nov. 



Subimago (dried). — Wings dark sepia-grey, with light reddish brown longitudinal 

 nervures. Setae sepia-grey. Legs of ? in opaque view yellowish testaceous ; in trans- 

 mitted light yellowish amber-colour. 



Imaffo [dried), <j . — Thorax jet-black above, at the sides pitch-black. Abdominal 

 segments 2-6 and the base of segment 7 transparent white, with opaque Avhite joinings 

 and burnt-umber brown ventral ganglia, the other segments pitch-brown above ; seg- 

 ment 8 beneath is moi*e of a warm sepia-brown, and segment 9 somewhat rusty or 

 reddened, the colouring extending a little into the forceps-basis. Seta? transparent, 

 white ; forceps-limbs cretaceous, tapering gradually from the base. Lobes of the 

 penis slender, each with a single short and slender acuminate barb-like lateral appendage 

 or process, projecting outwards obliquely at some distance before the tip. Fore legs in 

 opaque view bistre-brown or pitch-brown, changing in transmitted light to brownish 

 amber ; hinder legs in a large measure transparent whitish, but tinged with a similar 

 brownish tint towards the distal extremities of the femora and the extreme bases of the 

 tibiae, as well as in a still fainter degree towards the extremities of the tarsi. "Wings 

 vitreous, with the stronger longitudinal nervures light pitch-brown, changing with light 

 transmitted to brownish amber ; in the pterostigmatic space of the fore wing are about 

 8-12 slightly curved cross veinlets of a like colour, mostly simple and thickened towards 

 the subcosta ; in the remainder of the marginal area the cross veinlets are very indistinct. 

 Length of body, d 7o, wing 8 mm. 



Rab. Mt. Hood, Oregon (M^Lach. Mus.). 



Leptophlebia mollis. Hag. MS. Plate XI. 17 b (forceps, from side and wings). 



Cloe mollis, ! Hag., MS. (1861). 



Leptophlebia mollis, ! Etn., Trans. Ent. Soc. London (1871), 88, pi. iv. 28 [details]. 



Subimago {dried).— Wm^^ very light brownish white. Thorax dark brownish. 



hiago {dried).— 6 . Thorax above either pitch-black, luteo-piceous, or rufo-piceous. 

 Abdomen in segments 2-7 translucent whitisli, the tips of the dorsal and sometimes also 

 of the ventral segments greyish, and the ventral ganglia rufescent ; segments 10-8 and 

 the extremity of segment 7 rufo-piceous or luteo-piceous. Forceps-limbs dilated some- 

 what suddenly towards the base. Coxse and fore femora towards the tips in opaque view 

 somewhat light testaceous or rufo-piceous, changing in transmitted light to pale amber ; 

 hinder femora lighter ; the rest of the legs dirty whitish, the fore tibia at its extremities 

 slightly testaceous, and in some lights changing throughout to dull yellowish amber. 

 Wings vitreous, the neuration mostly colourless, but the subcosta, great cross vein, and 

 base of the costa in some lights slightly discoloured. Setae whitish or greyish, dark or 

 reddish at the joinings. 



2 . Body polished, dark pitch-brown, the dorsal abdominal segments darker at the 

 joinings. Setfe white. Legs all whitish, only faintly discoloured towards the ends of 

 the femora. Wing-nervures more nearly colourless than in the c? . Length of body 6-7, 

 wing 8 ; set. c^ im. about 11 ; 2 im. about 6 mm. 



