Mayfly Species Siphlonurus securifer (Gray Drakes)

A dark brown species with a dark mid-ventral line.

Thorax shiny deep blackish brown. Fore legs dull brown, with a faint brown apical band on the femur; tarsal joinings dark brown. Middle and hind legs yellowish brown; femoral band more distinct than on fore leg; tarsal joinings brown. Wings hyaline; all veins dark.

Abdomen deep shiny blackish brown dorsally. The anterior pale triangles are pale yellow. Ventrally pale yellow, with a continuous mid-ventral dark brown line. On each side of this line, near the center of each sternite, the usual small dark dot, and the usual lateral row of larger brown spots anterior to and laterad of the small dark dots. Forceps smoky brown. Tails dull smoky, the joinings brown. Penes as in fig. 123.