An aquatic insect in the process of rising to the surface and changing to a flying adult form. Often will have an attached trailing shuck which feeding fish may key upon.
A term for an aquatic insect at the stage when it swims to the surface or just below the surface to hatch or change from a nymph or pupa to an winged adult. 
pertaining to aquatic insects, the name used to describe that time frame when the nymph reaches the surface and the adult hatches out; the emerging nymph may well be the single most important nymph phase for the fly fishers to imitate.
pertaining to aquatic insects, the name used to describe that time frame when the nymph or pupa is at or near the surface and the adult hatches out; the emerging nymph may well be the single most important nymph phase for the fly fishers to imitate. 
pertaining to aquatic insects, the name used to describe that time frame when the nymph reaches the surface and the adult hatches out; the emerging nymph may well be the single most important nymph phase for the fly fishers to imitate.
A term for an aquatic insect at the stage when it swims to the surface or just below the surface to hatch or change from a nymph or pupa to an winged adult.
pertaining to aquatic insects, the name used to describe that time frame when the nymph reaches the surface and the adult hatches out; the emerging nymph may well be the single most important nymph phase for the fly fishers to imitate.