54 EEV. A. E. EATON ON EECENT EPHEMEEID^ OR MAYELIES. 



Hexagenia venusta, sp. nOT. 



SuUmago {dried), ? . — "Wings dull light brown-ochreous, with black, usually immargi- 

 nate cross veinlets. Setse uniformly light brown-ochreous. Legs brown ochreous, with 

 tarsi and the extremity of the fore tibia intense burnt-umber brown. — Variation. Tarsi 

 in a large measure concolorous with the rest of the legs ; but the ungues, terminal 

 joiiit, and the extreme distal edges of the other joints of the tarsi, and also a broad band 

 at the extremity of the fore tibia, dark burnt-umber. 



Imago {dried), 6 . — Thorax either very light yellowish bistre-brown, or light brown- 

 ochreous, varied on the meso- and metanotum with light yellow-ochreous, and with a 

 light purple-madder stripe on each side from the edge of the occiput to the fore wing- 

 roots. Abdomen translucent whitish chrome-yellow in segments 2-8, and then posteriorly 

 darker, marked in light purple-madder with the same pattern as the 2 ; but in segments 

 7-9 the dorsal vessel is edged to a greater or less extent with purple-madder : again, 

 the ventral median stripe is prolonged to the prosternum, and in every abdominal 

 segment but the last two contains a pair of pale dots placed transversely in, or a little 

 behind, the middle of the segment ; also at the bases of the respective ventral segments, 

 close to the joinings 2-8 and the spiracular borders, in the extreme anterior lateral 

 angles of the segments, are small triangular light purple-madder spots, one spot in each 

 angle. Setse marked with nearly the same colours as the abdomen, the purjile-madder 

 coinciding in certain cases with the joinings, in others with the distal terminations of 

 the joints, in otliers with the whole of every fourth joint as well so as to form bands of 

 colour each about a joint and a half in breadth in addition to rings ; in one example the 

 bands are nearly two and a half joints broad. Pore legs madder-brown, or purple-madder, 

 with the tibia brighter than the femur, and the tarsus dull, vmiformly dark in joints 

 1 and 5, but whitish towards the bases of joints 2-4. Hind legs translucent whitish 

 chrome-yellow, like the abdomen ; the terminal joint and the lower point of the penulti- 

 mate joint of the tarsus, light purple-madder. Wings transparent, and in a large extent 

 tinted almost imperceptibly with light yellowish, but coloured distinctly with raw- 

 umber in the marginal and submarginal areas of the fore wing (this colour receding 

 slightly from the costa between the cross veinlets in the proximal half of the marginal 

 area so as to leave the membrane clear thereabouts, and not extending nearer to the 

 wing-roots than the great cross vein), and sometimes with a more or less narrow blackish- 

 grey bordering along the terminal margin of the hind wing : neuration of diverse colours, 

 the costa, subcosta, and radius outside the great cross vein of the fore wing dark pitch- 

 brown, the remainder of the longitudinal nervures light yellowish (inclusive of the bases 

 of those three) ; cross veinlets black, sometimes narrowly edged with blackish in the 

 customary parts of the wings, but not so as to form spots. 



? . Body yellow-ochreous marked with violet-grey, viz. :— with a stripe on each side of 

 the pronotum reaching to the wing-roots ; on the dorsum of the abdomen, in segments 

 1-8 a series of oblique triangular spots, on each side one in every segment, the triangles 

 truncate posteriorly, and in segments 1-4 reaching from base to joining, but in the others 

 not starting from the base of the segment; in segment 9 the corresponding spots are 



