Epeorus are big nymphs. The mature larva can reach four cm. from head to cerci. It is a scraper nymph and it lives on rocks, anchoring with its aerodynamic profile,
that leverages on water current,to get better grip on stones. They hatch between May and July and nymphs in grown size are present from February to the beginning of summer.
At first glance and without a magnified view they look blackish. The pattern presented here is a good searching fly and imitates an Epeorus nymph that lost the grip and being
prey of the current.