Mayfly Species Paraleptophlebia bicornuta (Mahogany Duns)

This is a species with almost as much brown as white on the middle abdominal segments. Head and thorax blackish brown above, a little paler on the sides and beneath. Fore legs brown with paler tarsi; middle and hind legs paler beyond the brown femora. Wings hyaline with brown longitudinal veins; costal cross veins obsolete except in the stigmatic area where they are numerous, long, strongly aslant and sometimes forked.

Abdomen dark brown on the first segment above, lighter on the second, and reddish brown on segments 8 to 10; 3 to 7 whitish with brownish cloud on the posterior half of the dorsum of each. A black dot on the stigma and a diffuse roundish, brown spot above it. Mid-ventral areas also faintly tinged with brown, especially segment 7. Sternite 1 wholly brown; 8 and posterior half of 9 a bright reddish brown. The basal joint of the forceps is brown; the distal joints are white; at the base of the former is a conspicuous lobe above, similar to that in Paraleptophlebia debilis. Penes broadly separated by a very wide U-shaped notch; dilated and truncate at tips and bearing just before the tips on the dorsal side a pair of long flat lobes that converge by their rounded ends within the U-shaped cleft. Reflexed spur bifid, almost crescentic in form, attached by the back of this crescent; the outer horn longer (see fig. 135). Tails pale brown.