Mayfly Species Attenella margarita (Little Western Blue-Winged Olives)

A species of the simplex (now a synonym of Dannella simplex) group, of which only the nymphal stage is known; dorsal abdominal spines present, but no occipital nor thoracic tubercles.

Head and thorax of nymph smooth. Legs pale; tibiae and tarsi banded at the middle, tarsi also at the tips. 8 to 9 denticles along the inner margin of each claw, the distal one being longest. General color olive brown with blackish markings. Lateral extensions of the abdominal segments are well developed, and terminate in long postero-lateral spines on segments 4 to 9; abdomen broadest at segment 7. Gills present on segments 4 to 7 only, semi-operculate on segment 4. Rather short dorsal spines are present on tergites 3 to 9. Two color phases are known. In the best marked phase, a median blackish spot is present on tergites 2 and 3, and 5 and 6; apical margin of 8 with a black streak; tergite 9 largely blackish except for the lateral extensions and two pale submedian apical dots. Lateral extensions pale, each crossed near the middle by a broad brown band. Brownish ventrally; sternite 8 largely pale yellowish; sternite 9 blackish brown. Tails yellowish white, with a broad black band across the middle and a narrow black band at the tip.