Mayfly Species Ameletus vancouverensis (Brown Duns)

The wings of this species are tinged throughout with umber brown; penes with two very long median spines.

Head and thorax deep mahogany brown. Mesothoracic scutellum light yellowish brown; two lateral arms extend forward from this area, thus forming with it a yellowish U-shaped patch. Pleura shaded with paler brown. Fore legs deep smoky brown; middle and hind legs umber brown, the femora with indications of a ruddy apical band. Wings tinged strongly and throughout with umber brown; stigmatic area even deeper brown; cross veins of the stigma anastomosed; both longitudinal and cross veins are dark brown, the cross veins very numerous. First abdominal segment deep mahogany brown; tergites 2-7 semi-hyaline, shiny light yellowish brown, the posterior margins narrowly dark brown, and the posterior half of each tinged with diffuse brownish shade. Tergites 8-10 are opaque, deep mahogany brown, tinged anteriorly with yellowish brown. Sternites 2-8 light ochreous, with a wash of dull brown; sternite 9 is rather bright yellow-brown in the central area, its base and lateral areas dark brown. Forceps base yellowish brown in central area, the apical and lateral margins mahogany brown; penes brown-tinged. Two long sharp spines are present between the lateral portions of the penes (see fig. 118). Tails deep smoky, joinings darker.