Mayfly Species Rhithrogena virilis

A large species with the usual almost unicolorous, brown coloration. Head brown with ochreous shading around bases of antennae and the anterior portion suffused with smoky. Notum brown, with the scutellum and adjacent parts light ochre-brown; pleura shaded with ochreous, particularly anterior to base of wings, a dark streak from base of forewing to pronotum; sternum tinged with smoky in median area. Abdomen brown, irregularly paler along lateral edge and on posterior segments ventrally. Forceps and setae deep smoky. Forelegs deep smoky; mid and hind legs lighter brown with the usual smoky streak on each femur. Wings hyaline with a faint tinge of amber along costa; veins and crossveins fine, deep brown, the latter anastomosing as usual in pterostigmatic region.

Head suffused with smoky anterior to antennae; area between ocelli and antennae light ochreous; next the eyes and posterior to ocelli light ruddy brown with a slight median smoky tinge and the vertex in lateral angles slightly ochreous. Otherwise very similar to male, but with slightly paler thorax.