Mayfly Species Heptagenia elegantula (Pale Evening Duns)

A yellowish species; reddish brown dorsal stripe on mesonotum, black markings on pleura above coxae; genitalia as in fig. 94.

Head pale yellowish; a reddish spot on frontal carina, and red shading on vertex between eyes and ocelli. Thoracic notum pale yellowish; a median reddish brown stripe on mesonotum, and pinkish area anterior to scutellum. Pleura and sternum likewise yellowish; pinkish areas on pleura below base of each wing; a black streak above base of middle and hind coxae, and a black spot posterior to hind coxae. Fore leg light bronzy brown; femur indistinctly banded at middle with light reddish brown, red-brown also at apex; apex of tibia, distal tarsal joint and tarsal joinings, also claws, dull reddish to blackish brown. Middle and hind legs yellowish amber; no median femoral band; tip of tibia not darkened. Basal joint of fore tarsus about 1/6 the length of the second joint. Wings hyaline. Costal margin of fore wing may be tinged with pale lemon yellow, with greenish or bistre-grey. Subcosta and radius yellowish amber in basal half; other longitudinal veins fine, pitch brown to black. Humeral cross veins thickened posteriorly, blackish. Cross veins dark; those in costal space thicker than others, black; a well-marked black bulla.

Abdominal segments pale; 2-7 semi-hyaline, 8-10 opaque. Posterior margins of tergites 2-7 smoky greyish or brownish; tergites 8-10 tinged with pink. Sternites pale yellowish. Tails pale yellowish, joinings dark brown. Genitalia distinctive.