262 EEV. A. E. EATON ON EECENT EPHEMERIDiE OE MATFLIES, 



oblique lateral stripe from the hinder border to the spiracular line, and a fine abbreviated 

 streak from the hinder angle of the dorsum along the same line, intense purple-madder- 

 brown, or purple-black; venter unicolorous. Setae light burnt-umber brown. Legs 

 dull translucent rufo-lutescent, almost rufous, the fore leg with the apical projection of 

 the tibia pitch-brown, and the tarsus light brown-ochreous. Wings vitreous ; the fore 

 wing from the base to tlie pterostigmatic space in the marginal and submarginal areas 

 faintly tinted with light yellowish-green, and from thence to the apex coloured with 

 raw-umber brown ; the hind wing in the larger portion of the marginal area tinted with 

 light yellowish-green, and along the terminal margin narrowly bordered with black- 

 grey or brown-black ; longitudinal neviration mostly pitch-brown, the costa of the fore 

 wing in some lights seeming darker, and the nervures near the wing-roots, the svibcosta 

 and radius for some little distance farther, and the great cross vein, light raw-amber ; 

 cross vcinlets pitch-black. 



? . Neviration of wings pitch-black, excepting the bases of the costa and subcosta, the 

 great cross vein, and the proximal extremities of the longitudinal nervures posterior to 

 the radius, Avhich are very light raw-umber brown. Legs rufo-lutescent, with the 

 terminal joint of every tarsus intense warm sepia-brown. Egg-valve acute ; ventral lobe 

 of the penultimate segment entire, and traversed by a median longitudinal fold. Length 

 of body, c? (large example) 18, 2 16 ; wing, d 11-15, S 21 ; set£E, 6 im. 48 (or more), 

 2 54 mm. 

 Hub. China, Hong Kong (Brit. Mas.). 



Thkee Nymphs, generis incerii, of the Ecdyurus type. 



Nymph No. I. — PI. LVII. (whole figure and details). 



Six anterior pairs of the abdominal tracheal branchiae provided with broad, pointed 

 laminae recumbent upon the sides of the dorsum ; seventh pair spreading, the laminae 

 linear-lanceolate and minute. Each of the anterior laminae is oblique, somewhat obovate 

 and cuspidate, but is asymmetrical, the lower margin being either truncate obliquely or 

 sinuate, and the opposite side slightly dilated, between the base and the widest part of 

 the lamina, while the cusp is nearer the upper than the lower edge ; each contains a 

 strongly defined fruticosely branched trachea, and partially overlies the branchial 

 filaments, which are not fascicled in the usual manner, but explauate, and connected 

 together by their membrane for some distance from the roots, thus constituting a single 

 subrotund lamella, fringed deeply with long branching filaments, annexed to the base 

 of the lamina. The hindermost laminae each contain a ji innately branched trachea, and 

 are pilose at the edges, but apparently lack fibrils. Median caudal seta subequal in 

 length to the others and to the body ; their joinings beset with minute spreading hairs. 

 Pronotum transverse, very short, well defined behind ; its lateral margins slightly 

 dilated ; its posterior margin rounded off obtusely towards the sides, and sinuate in the 

 middle. Ventral segments 2-5, short, the hinder ones successively longer ; the lobe of 

 the ninih segment of 2 elliptical at the tip, and sinuate on each side thereof ; pleurse 



