Mayfly Species Drunella allegheniensis

A species of the fuscata (now a synonym of Drunella walkeri) group, allied to E. tuberculata (now a synonym of Drunella tuberculata). Only the nymph is known. Separated from the latter species by the greater development of the occipital and thoracic tubercles, the widely flaring lateral margin of segment 8, and the lack of long hairs on tergites 8 and 9. See fig. 51.

Short blunt frontal horns are present, and a frontal shelf which is slightly notched laterally (see fig. 151e). Occipital tubercles high and prominent. Tubercles present also on the pronota and mesonota. Fore femur with numerous spines on the anterior margin and a few on the posterior. All femora flattened, the fore femur widest. Tibial ‘thumb’ well developed. Fore tarsus distinctly widened apically. Dorsal abdominal spines present, best developed on tergites 5-7. Gills borne on segments 3-7. No fringe of hairs on the posterior margin of tergites 8 and 9, as in tuberculata. The lateral extension of segment 8 flares outward widely at about the middle of its length. General color (in life) greenish brown with black markings. A transverse black band between the eyes; black streaks on the occipital tubercles; wide and prominent black markings on pronota and mesonota; black lateral patches on abdominal tergites 3, 4, 6 and 7. Legs yellowish with indistinct brown markings. Venter of abdomen yellowish; a lateral row of black dashes on each side; black submedian streaks; and a curved row of four black dots. Tails yellowish to reddish brown; near the middle, 4 or 5 narrow bands of white.