Mayfly Species Epeorus dulciana

A species of the albertae (now a synonym of Epeorus albertae) group; blackish markings on thoracic pleura; apical margin of forceps base as in I. sancta-gabriel (now a synonym of Epeorus hesperus).

Head yellowish; antennae dusky. Red patches on vertex of head of female, between eyes and ocelli, and posterior to median ocellus; posterior margin of occiput blackish. Thoracic notum pale brown. Lateral and posterior margins of pronotum blackish. A reddish streak on each side of anterior portion of mesonotum. Posterior portions of mesonota and metanota somewhat darker brown; dark median streak on mesonotum. Pleura and sternum yellow-brown. Creamy markings on pleura; a red-brown streak from pronotum to base of fore leg, another anterior to middle leg. Black dots on and above all coxae. Legs yellowish to olive brown. Tip of fore tibia, claws and tarsal joinings blackish brown. Median blackish spot on each femur, also a narrow red-brown apical band. Fore femur very slightly shorter than tibia. Wings hyaline. Venation yellowish in male, cross veins indistinct except those of stigmatic area, which are 9-11 in number. Humeral cross vein black near subcosta.

Abdominal tergites yellowish to olive brown; posterior margins narrowly blackish. Sternites slightly paler. Tails yellowish to olive brown, joinings faintly darker. Genitalia as in fig. 107, "n. sp., McD.” The black thoracic markings ally this species to I. sancta-gabriel and I. youngi (now a synonym of Epeorus albertae). Differences in detailed structure of the penes separate it from both species; the pale venation of the male also serves to distinguish it from the former species. The apical margin of the forceps base is much more produced than in I. youngi.

In female, venation rather dark brown; veins fine but distinct.