Mayfly Species Eurylophella minimella (Chocolate Duns)

A member of the bicolor group (now a synonym of Eurylophella bicolor), rather close to E. bicolor (now a synonym of Eurylophella bicolor). Thorax and abdomen of imago darker brown than bicolor, the legs brighter yellow, and with a distinct brown spot apically on each femur.

Eyes orange. Head yellow with brown shading at the bases of the ocelli. Thoracic notum very dark brown, with yellow shading laterally and in the sutures. Sternum rather bright brown. Legs quite bright yellow; coxa tinged with brown, and with a black spot; near the apex of each femur is a distinct brown spot. Wings hyaline. Abdominal tergites 1-7 dark brown, 8-10 with paler shading; tergites 1-4 tinged slightly with smoky sub-dorsally. A narrow brown dorsal line is present, and a pair of blackish subdorsal dots near the anterior margins, which are fainter on the posterior tergites. On tergites 8 and 9 the dorsal line and the subdorsal dots coalesce. Short oblique black streaks and longitudinal black lines are present at the stigmatic region. Ventrally pale brown, the last two sternites creamy. On sternites 2-7, the usual curved row of dark dots is distinct. Tails pale, joinings blackish.

Occipital tubercles are wanting in the male nymph. Postero-lateral spines are very poorly developed on segments 2 and 3. Dorsal spines longer, thinner and more upright than in the closely related bicolor (now a synonym of Eurylophella bicolor), especially those on tergites 5-7, which are twice as long as in bicolor. The rows of spines are evenly divergent to rearward, and not suddenly widened on tergite 5. Tails not banded.