Mayfly Species Siphlonurus rapidus (Gray Drakes)

A medium-sized light brown species, having a discontinuous mid-ventral brown stripe.

Head grey to yellowish. Thorax dull yellowish to olive brown. Mesonotum yellowish, shaded with reddish brown on the median area. A pale spot before the scutellum. Scutellum reddish brown. Purplish streak anterior to wing roots. Pleural sutures yellowish. Pale bands across the mesosterna and metasterna. Fore leg yellowish brown, the tarsi yellowish; joinings purplish brown. Middle and hind legs yellowish, the femora washed with purplish brown; joinings purplish brown. Wings hyaline, very faintly tinged with brown. Stigmatic area opaque whitish. Veins dark purplish brown. All costal cross veins distinct, brown; about 11 before the bulla, 21-23 beyond it, in the stigmatic area. The latter veins are occasionally forked and anastomosed near the costal margin.

Abdomen purplish brown dorsally. The usual dark lateral triangles present, more or less diffuse; dark oval spots small, indistinct. Pale anterior triangles semi-hyaline, whitish; much reduced in size on the basal and apical tergites. Ventrally pale yellowish white, with a discontinuous dark purplish brown mid-ventral streak. Sternites 1 and 2 largely purplish brown. Forceps base yellowish white, forceps and penes brown. Tails yellowish white, joinings purplish brown. Genitalia as in fig. 122.