Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
Most physical descriptions on Troutnut are direct or slightly edited quotes from the original scientific sources describing or updating the species, although there may be errors in copying them to this website. Such descriptions aren't always definitive, because species often turn out to be more variable than the original describers observed. In some cases, only a single specimen was described! However, they are useful starting points.
Abdominal tergites of male imago deep brown, sternites paler brown; longitudinal veins brown.
Head and thorax deep brown; lateral flange-like edge of mesonotum paler; thoracic sternum deep brown. Legs dull amber, the fore legs deeper in color than the second and third pairs. Wings hyaline; longitudinal veins brown; cross veins pale, almost invisible except in the anal region. Abdominal tergites deep brown: sternites paler brown. Forceps dull dirty amber colored; tails pale brownish, the joinings darker.
The nymph possesses both dorsal and lateral spines on the mesonotal shield; the frontal projections are reduced to very small blunt tubercles; the genae are very slightly produced only. The dark longitudinal veins separate this species from Baetisca obesa, in which the veins are largely pale.