Mayfly Species Ephemerella catawba

A species of the Ephemerella needhami group; usually without spines on the penes; venation pale.

Head light brown; eyes light orange. Thorax reddish brown. Pronotum margined laterally with pale yellow, mesonotum blotched with yellow. Mesonotal scutellum and metanotum darker brown. Pleura brown, with yellow markings. Sternum brown; metasternum shaded with purple anteriorly. Fore leg light reddish brown, claw and last two tarsal segments greyish. Middle and hind legs white; claws and tarsi washed with light brown. Wings hyaline; veins colorless, except the three main veins of the costal margin, which are tinged with yellow. Stigmatic area opaque, cross veins anastomosed.

Abdomen olive brown dorsally; tergites 1-6 with purplish brown markings. Tergites 7-9 light chestnut brown; purplish brown submedian lines on 7. Anterior margins of tergites yellowish, posterior margins dark brown. Median line faintly greyish white; pleural fold greyish white. Sternites 1-6 greyish white with lavender tinge; sternite 1 chestnut brown on anterior and lateral margins. Faint darker submedian dashes, and dots near the median line. Tails smoky white at base, silvery white beyond; joinings purple. Penes as in fig. 155.

Nymph slender, smooth; olive green to brown, with or without white patches on abdominal tergites 4-7. Thoracic notum and legs mottled with yellow and brown. Fore femur smooth; two dark bands. No dorsal spines on abdomen. The flattened lateral margins are prolonged into sharp spines, yellow in color. Ventrally paler than above, usually without markings. Tails yellowish to reddish brown, with several narrow yellow cross bands. Usually found in moss on rocks, in rapid water.