Mayfly Species Caudatella heterocaudata

Eyes reddish-brown. Thorax olivebrown, yellowish patch anterior to the base of the wing, containing a black line which descends to the coxa of the foreleg; lateral sutures marked with black; legs pale olive-brown; fore femora and tibia with black markings; wings hyaline with pale veins and cross veins. Abdominal terga olive-brown, anterior half of each of the first four segments with broad black bands, bands on posterior segments reduced to large semicircular dorsal patches; sterna pale olive-brown with ~midventral and sublateral longitudinal dark brown stripes as in fig. 7. Caudal filaments brown, lateral cerci 20%-30% as long as terminal filament. Penes with a shallow median apical depression as in fig. 3.

Similar to male except for usual sexual differences.

Cerci 2-3 mm long; terminal filament 10-12 mm long. Head brown with pale markings, roughened but without occipital tubercles; antennae brown ; maxillary palpi three-segmented as in fig. 12. Thorax brown; legs brown, femora with a few marginal spines and a distinct row of marginal hairs, tibiae and tarsi with a distinct row of marginal hairs (fig. 15), tarsal claws with three to seven denticles. Abdominal terga olive-brown; anterior half of each of the first four segments with broad black bands, bands on posterior segments reduced to large semicircular dorsal patches; each tergum with a series of lateral black patches; paired dorsal abdominal tubercles on segments 1-9 or 2-9 as in figs. 1 and 23; sterna pale olive-brown with median and paired sublateral longitudinal dark brown stripes as in fig. 7. Caudal filaments light brown, darker at the joinings; lateral cerci 20% to 30% as long as terminal filament.