Mayfly Species Anafroptilum minor (Tiny Sulphur Duns)

Abdominal tergites 2-6 of male imago hyaline; large lateral purplish brown blotches on each.

Head and thorax deep blackish brown. Anterior margin of metanotum tinged with purplish. Pleura and sternum largely dark; slight ruddy tinges anterior to the wing roots. Legs whitish; femora with traces of a ruddy median spot. Wings hyaline, venation pale. First cross vein of the radial sector considerably nearer the base of the wing than the following vein. Abdominal tergites 2-6 hyaline; geminate purplish brown dorsal dashes and large lateral blotches of the same color on each; on tergites 3 and 6 the lateral blotches coalesce dorsally, so that only the anterior portions of these are hyaline. Sternites 2-5 hyaline, each with a brown patch along the lateral margin on each side, and with transverse blackish dashes on the posterior margin, one on each side of the median line. Tergites 7-10 opaque, deep brown tinged with purplish; sternites light creamy brown, opaque; the posterior margin of sternite 9 shaded with purplish. Tails and forceps pale.

This species is distinct from all others thus far described, by reason of its small size and brownish abdominal blotches.