Mayfly Species Siphlonurus luridipennis (Gray Drakes)

A very large dark species, known only from a female imago of the type material.

Head blackish. Frontal margin of clypeus yellowish. Usual dark transverse band across median carina, and dark median streak on vertex and occiput. Thorax rusty to chestnut brown. Pronotum brownish black, the lateral and posterior margins yellowish. Pleural and mesonotal sutures yellowish. A yellow area anterior to the scutellum. Sternum dark rusty brown, sutures yellowish.

Fore leg clear yellowish umber brown; femur darker toward the apex; knee somewhat clearer; tibia and tarsus light reddish brown. Middle and hind legs amber brown, joinings reddish brown. Wings hyaline, tinged faintly with grey, especially in the stigmatic area. Costa greenish yellow at the base. 11-13 costal cross veins before the bulla, 22-25 in the stigmatic area. The latter forked near the costa and anastomosed, forming a two-ranked network.

Abdomen smoky yellowish or greyish red dorsally, with diffuse dark shading, so that it appears very dark. Posterior margins of tergites dark, as well as the usual lateral triangles and oval spots. Median line also dark. Tergites 8-10 brighter in color, the oval spots smaller but more prominent. A short postero-lateral spine on segment 9. Ventrally blackish, the apical sternites dark reddish brown. Posterior margin and anterior angles of sternites yellow; lateral margins reddish yellow; dark spots very indistinct. Tails broken.