EEV. A. E. EATON ON EECENT EPHEMEEID^ OE MAYFLIES. 243 



BLEPTUS, gen. nov. 



Illustrations. Achilt (detail) PI. LXV. 1. 



Adult. — Eirst joint of the hind tarsus rather longer than the second ; first joint of 

 the 6 fore tarsus also longer than the second ; ungues each unlike the other ; penis 

 lobes when dried conformable to those of normal species of Bliithrogena ; hind wings 

 unusually small, destitute of axillar neuration. — Fore leg of <s about li as long as the 

 body ; tarsus nearly 1\ as long as the tibia, and this about 1-^^ as long as the femur ; 

 the tarsal joints in the order of their shortening rank 1, 2, 3, 4, 5. Hind tarsus of 

 6 about f as long as the tibia, and this l^f as long as the femur ; the tarsal joints in 

 order of shortening rank 1 equal to 5, 2 subequal to 3, 4. Ungues in every tarsus 

 each unlike the other. Forceps-basis of d bifid, but only slightly emarginate in 

 the middle of its posterior border, and not produced into projecting lobes at the 

 bases of the limbs ; the short proximal joint of each limb is well defined. Penis lobes 

 tubular, curved very slightly outwards, but contiguous at the roots ; orifices of the 

 seminal ducts terminal. Outer caudal setae of d 3i as long as the body. Only the 

 adult 6 is known. 



Type. JB.fasc'mttis, sp. nov. 



Distribution. Japan. 



Etymology. /SAeTrroc, worth seeing. 



Bleptus fasciatus, sp. nov. Plate LXV. 1 (hind wing). 



Imago {dried) 6 . — Notum dark brown-ochre. Dorsum of abdomen light brown-ochre, 



with the joinings of the segments and a fine longitudinal median line pitch-brown or 



intense warm sepia ; segments 8-10 rather darker than the others : venter spotless. 



Setae warm sepia-brown, dark at the roots. Porceps-limbs slightly brownish ; the basis 



concolorous with the venter. Femora and tibiae in opaque vieiv light raw-umber brown, 



dark just at the knee, and piceous at the extreme tip of the fore tibia : tarsi dull light 



yellowish, the fore tarsus approaching the lightest tints of Roman ochre or raw sienna, 



and having the terminal joint and ungues light raw-umber brown ; but the hinder tarsi 



are lighter and more uniform in tint. In transmitted light the general colouring of the 



femora and tibise becomes a rich yellow amber, and that of the tarsi whitish amber, with 



the joinings of the hinder tarsi slightly opaque. Wings vitreous, with brownish or 



greyish markings : in oimque vieto of the fore wing the marginal and submarginal areas 



are of a light raw-umber bro^vn tint, which in the pterostigmatic region acquires a slight 



iegree of opacity ; a narrow, irregular fascia, curved outwards a little, and of rather a 



greyer brown (approaching light bistre) than the said areas, crosses the wing almost 



lirectly from the radius to the vicinage of the extremity of the anal nervure, and there- 



ibouts becomes slightly dilated, running inwards a little along the margin of the anal- 



ixillar interspace ; a cloud of the same colour as the fascia, concave inwards, occupies 



he extremity of the wing posterior to the radius, and the same colouring borders more 



•r less narrowly the remainder of the terminal and inner margins : in transmitted light 



ery little difference is perceptible between the tint of the marginal and submarginal 



reas, and that of the markings of the remainder of the fore wing. A broad intense 



