Mayfly Species Anafroptilum album (Tiny Sulphur Duns)

Abdominal tergites 2-6 of male imago entirely hyaline.

Turbinate eyes dull orange-brown, in dried specimen. Head blackish brown; whitish ochreous tinges in median area behind ocelli. Pronotum blackish with paler patches laterally. Mesonotum pale ochreous with brown shading; scutellum and posterior portion almost entirely white, shaded faintly with pink. Metanotum deep brown; anterior margin white with pinkish shading and a median dark dot. Pleura and sternum mostly deep brown, with faint white shading at the intersegmental areas. Legs white. Wings hyaline, venation pale. Hind wing very narrow, much as in C. fragile (now a synonym of Procloeon fragile), but not quite as long; costal projection prominent. Abdominal segments 2-6 entirely hyaline; segments 7-10 opaque whitish. Tails white. A slight inward bulge on the inner margin of the second forceps joint.

This species is allied closely to C. convexum (now a synonym of Anafroptilum album); the hind wings are considerably more narrow than in that species, and the tubercle on the second forceps joint less well developed.

Described as C. convexum

Body length 4 mm, wing length 5 mm

Abdominal tergites 2-6 of male imago hyaline white, sometimes with a median pinkish shading.

Turbinate eyes pale chestnut brown in dried specimen. Head brown, with darker brown markings at bases of antennae and on median carina. Prothorax brown. Mesonotum brown, the pleura and scutellum marked with ochreous white. Metanotum pinkish on the anterior margin, brown in posterior half. Legs pale yellowish. Wings hyaline. Hind wing moderately broad, the costal projection prominent (see fig. 165).

Abdominal segments 2-6 hyaline white, sometimes tinged faintly with pinkish in the median area. Segments 7-10 opaque white, the tergites with a pink flush, most noticeable on 9, where it appears as a pink lateral border. Tails white. Second joint of forceps with a distinct inwardly projecting tubercle.

From the closely-allied C. album (now a synonym of Anafroptilum album), this species may be separated by the pink lateral margin on tergite 9, the somewhat darker thorax, the wider hind wing, and the greater development of the tubercle on the second forceps joint. It is somewhat smaller than C. walshi (now a synonym of Anafroptilum album), and is distinguished from it by the brown thoracic sternum and posterior half of the metanotum, which areas are creamy white in C. walshi.

Described as C. walshi

Body length 6 mm, wing length 6 mm

Abdominal segments 2-6 of male imago hyaline white, with no markings except a broken black spiracular line.

Turbinate eyes pale yellow in living insect, bright reddish in dried specimen. Pronotum light ochreous brown; mesonotum similar, shading into creamy on the posterior third. Metanotum and all of the sternum creamy. Legs whitish. Wings hyaline, venation pale. Abdominal segments 2-6 hyaline white, with a broken black line along the spiracular area. Tergites 7-10 opaque, creamy, shaded with light purplish brown (perhaps due to discoloration); sternites similar, but with no dark shading. Tails whitish. Between the bases of the forceps is a plate having a convex posterior margin. The inner margin of the second forceps joint bears a distinct tubercle.

This species may be distinguished from the allied C. album (now a synonym of Anaafroptilum album) by the stronger tubercle on the second forceps joint, and the pale metanotum and thoracic sternum; these areas are wood-brown in album, which is also considerably smaller in size.

The gills of the nymph are single on all segments; the dorsum of the abdomen is largely shaded with dark color.

Described as C. convexum

The nymph is closely allied to C. album (now a synonym of Anafroptilum album), with single gills on all segments, but the dorsal abdominal markings are more restricted, the last four segments being largely pale.