Mayfly Species Eurylophella funeralis (Chocolate Duns)

A species of the bicolor group (now a synonym of Eurylophella bicolor), quite close to E. temporalis (now a synonym of Eurylophella temporalis), but considerably darker.

Eyes orange. Head yellowish brown; a black spot below each antenna, next to eye. Vertex shaded with blackish. Head of female deep yellow, vertex brown. Thorax reddish brown. A median depressed O-shaped area on the pronotum, sometimes outlined in rose color; on the anterior margin the lateral carinae around this depression run up into a spine. A rose-colored mark near the lateral margin on each side; blackish pencilings near the median line. Mesonotum yellowish laterally; median line dark red; a median geminate black streak just anterior to the scutellum. A blackish streak before each wing root, surrounded by a yellow area. Coxae brown-tinged, with a purplish black transverse streak. Fore leg amber, other legs paler yellow; claws and tips of last tarsal joint dusky. Wings hyaline; venation pale, the main veins of the costal margin yellowish.

Abdominal tergites reddish brown, 8-10 darker. Posterior margins, pleural fold, lateral streaks, a narrow median line, subdorsal streaks and stigmatic marks blackish brown. A pale yellowish area on each side of the dark mid-dorsal line. Sternites somewhat paler reddish brown. Oblique black dashes and dark dots distinct. Ganglionic areas blackish brown, on middle sternites. Tails yellowish brown at the base, whitish apically; joinings purplish black. Genitalia dark reddish brown.

Occipital tubercles of the nymph well developed, rounded. The rows of dorsal spines diverge distinctly to rearward. The spines on tergites 1-3 are thin, tapering and very erect. The lateral extensions and postero-lateral spines are better developed in this species than in any other of the bicolor group (now a synonym of Eurylophella bicolor); the spine on segment 9 is fully twice as long as its width at the base. The lateral margins of segment 9 are subparallel, the spines at the tip being distinctly incurved. General color brown, rather unicolorous; markings of the femora very indistinct; operculum unmarked or with faint pale dots. The usual curved row of dark dots on the sternites is absent, but the short dark oblique dashes are present. Tails unicolorous brown; joinings of a few of the basal segments darker brown.