Other Common Names: Lesser green drake
Scientific Name: Drunella flavilinea

Like their larger cousins, the green drakes (D. doddsi, D. grandis ), flavs are crawler mayflies whose nymphs live in cold waters with moderate to fast flow. Nymphs are seldom available to trout until the emergence season, when they move to slower flows.

Because emergence is in slower water, your imitation needs to be reasonably accurate. So does your presentation: don't blind cast; wait until you see a trout rise to a natural, then gently, cast to that trout, leading it by a few feet.

Hatches are mid- to late-summer through early October. Hatches begin in the afternoon. Spinner falls can be important.

Flavs are nearly identical to slate-winged olives (D. coloradensis) except that slate-wings prefer slightly cooler water.


How to Match a Flav

Hatches are matched from Westfly's database of "standard" fly patterns.

Size 12-14 Poxyback Green Drake, Hares Ear, Pheasant Tail. Light olive body, dark wing
Runs below riffles and moderate-fast runs: indicator, tight line, shallow nymph
Size 12-14 Hackle Stacker, Film Critic, Green Drake Cripple. Light olive body, dark wing
Slow-moderate runs: standard dry fly
Size 12-14 Comparadun, Sparkle Dun, Green Drake Paradrake, Hairwing Dun. Light olive body, dark wing
Slow-moderate runs: standard dry fly


NYMPH COLOR: Brown with some dark olive

DUN SIZE: 7-13 (1/4-1/2 in) mm

DUN COLOR: Wings--smoky gray to dark gray. Body--olive, yellow-olive

SPINNER SIZE: 7-12 mm (1/4-1/2 in)

SPINNER COLOR: Wings--clear. Body--dark yellow-olive

OTHER CHARACTERISTICS: Nymph--beefy front legs with serrated edges; three tails. Dun and spinner--three tails; the front edges of the back wings have rounded points.