Keys used for
this identification

Filum terminale of at least five segments.

Cerci with long, thick hairs on the inside edge.

Tibia and femur of fore leg without long, thick hairs on their upper edge.

Distinct spines on the edge of each gill.

THE WOLFSBACH BENTHOS REPORT

Species Baetis rhodani

Lot of nymphs had black wing-case and were ready to hatch. A few winged insect were already in the air.