Mayfly Species Procloeon ozburni (Tiny Sulphur Duns)

Abdominal tergites 2-6 of male imago hyaline white, the posterior margins narrowly chocolate-brown.

Head and antennae blackish; tip of antennae white. Thorax unicolorous deep blackish dorsally, the pleura and sternum slightly more brownish; anterior edge of mesosternum tipped with pale ochreous. Legs whitish; traces of a ruddy median band on the femora. Wings hyaline. Hind wing long and narrow, two longitudinal veins (see fig. 165). Abdominal tergites 2-6 hyaline white; traces of an interrupted brown geminate mid-dorsal line; a narrow band of chocolate brown on the posterior margin of each, this band barely attaining the spiracular area. Tergites 7-10 chocolate brown, sternites alabaster white. Sternites 2-6 hyaline white, with very faint traces of brown posterior margins, most evident on 5 and 6. A blackish line marks the spiracular area. Tails white.

The dark thorax and the deeper brown of the posterior abdominal tergites distinguish this species from C. bellum (now a synonym of Procloeon bellum). The darker color and more prominent banding of the abdomen separate it from fragile (now a synonym of Procloeon fragile).

The nymph of specimens is much like that of C. bellum (now a synonym of Procloeon bellum), but has a broad band of brown on sternite 9, also lateral markings on some of the other apical sternites, and the sternites margined posteriorly with brown.