Mayfly Species Procloeon simplex (Tiny Sulphur Duns)

Abdominal tergites 2-6 of male imago pale whitish hyaline; traces of a black spiracular hair-line.

Turbinate eyes light green in living insect, pale orange-yellow in dried specimen, base deep brown. Head and thoracic notum dark blackish brown; posterior margin of pronotum creamy with a ruddy brown dot; antero-lateral margins of mesonotum paler brown, its posterior margin, the scutellum, and a small patch anterior to it, creamy. Anterior margin of metanotum creamy; pleura largely creamy, with tinges of ruddy brown. Prosternum whitish; mesosterna and metasterna largely brown, the central and lateral areas with creamy shading. Legs wholly pale whitish. Wings hyaline, venation pale; 6 to 7 cross veins in the stigmatic area, no granulations between them. Intercalaries of the 1st and 2nd interspaces wanting. First cross vein between radius and radial sector in a line with the following one.

Abdominal segments 2-6 pale hyaline whitish, with traces of a black hair-line along the spiracular area. Tergites 7-10 opaque, bright chestnut brown, with creamy lateral shading; posterior portion of 10 also creamy. Sternites wholly pale creamy. Tails and forceps white.

The paler eyes, pale thoracic markings and lack of red dots on the abdominal tergites distinguish this species from C. rubropictum (now a synonym of Procloeon rubropictum). The wholly pale legs separate it from C. vicinum (now a synonym of Procloeon vicinum), in which the bases of the fore legs are fulvous.