Mayfly Species Stenonema exiguum

A small species of Stenonema pulchellum group, allied to S. integrum(now a synonym of Stenonema mexicanum subspecies integrum); no dark spiracular dots; hind wing dark-margined; tail wholly pale.

Head pale whitish; faint reddish dot at center of vertex, no other marks; antennal filament dusky at base. Thorax pale creamy white, immaculate. Legs pale creamy white. Median and apical rose-colored or lavender bands on all femora; rose-colored spot at apex of tibia on middle and hind legs. Tip of fore tibia purplish black; tarsal joinings narrowly dark. On all tarsi, claws and distal half of apical joint dusky. Basal joint of fore tarsus slightly more than one half the length of the second. Wings hyaline, iridescent. Costa, subcosta and radius yellowish brown; other longitudinal veins pale yellow; humeral cross vein purplish black; other cross veins prominent, very dark brown; 4 basal costal cross veins, 8-9 beyond bulla. No tendency toward crowding of veins at bulla, as in S. integrum(now a synonym of Stenonema mexicanum subspecies integrum); tendency for serial arrangement of veins below bulla less evident than in that species. Distinct reddish stain in stigmatic area. Outer margin of hind wing narrowly dark; all veins colorless.

Abdominal segments 1-7 hyaline white; posterior margins of all tergites narrowly purplish black in dorsal area. No dark spiracular markings. Segments 8-10 opaque creamy whitish. Genitalia very similar to those of integrum; forceps relatively longer than in that species. Tails white, not darker at joinings.