Mayfly Species Serratella micheneri (Little Dark Hendricksons)

A member of the serrata group (now a synonym of Serratella serrata); yellowish with brownish markings; tails white, joinings dark; two or three blunt processes on the apical margin of each division of the penes.

Eyes orange. Head yellowish shaded with brown. Thorax yellowish, with brownish black markings; a dark band and streak on the prothoracic pleura; scutum, scutellum and median line of mesonotum margined with dark brown; two lateral dark streaks and three median dots on metanotum. Two blackish streaks on the pleura anterior to the middle and hind legs; coxae black-marked; median areas of the prosterna and mesosterna outlined in black, ganglia of the mesosterna and metasterna darkened. Legs yellowish; fore tibia and tarsus pale smoky. A narrow reddish brown apical band on each femur. Claws and basal tarsal joints smoky. Wings subhyaline to hyaline; venation pale. A purplish streak on the membrane of the fore wing near the base, below the costa; a brownish spot at base of costa and subcosta.

Abdominal tergites brownish; 2-8 rather heavily shaded with reddish to olive brown laterally. Posterior margins pale; brownish black stigmatic marks; pleural fold pale. Sternites yellowish; ganglionic areas purplish black; a reddish brown streak or triangular area borders the pleural fold, on each side. Genitalia yellowish. Two or three blunt processes are present on the apical margin of each division of the penes (see fig. 156). Tails white, joinings purplish black.

Head and thorax of nymph smooth; maxillary palp rather well developed. Thoracic ganglia and the anterior margins of the prosterna and mesosterna blackish. Legs pale yellowish; a black spot at base of tarsus; apex of tarsus, and claw, blackish brown. 7 to 8 denticles on each claw. Dorsal spines present on tergites 2-8; short on 2 and 8, longest on 5-7. Extensions of abdominal segments and the postero-lateral spines short; no spine on segment 8. General color yellowish to yellowish brown, the basal and middle tergites shaded with black. Blackish lateral patches are often present on the middle tergites. Ganglionic areas of the sternites are darkened; a double row of curved brown marks is present on each side. Tails alternately yellow and brownish black.