Stone fly imitation as tied by Wes Wyatt.
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Material list

1. Black 6/0 thread
2. 3906b 2x in hook sizes 10-14
3. Tail black goose biots
4. Body black chenille
5. Wing case black goose or duck quill may be omitted
6. Thorax yellow dubbing or yellow chenille
7. Legs black saddle hackle

Very simple basic nymph, when Stone flies are on the water.

Wind black 6/0 nylon thread to bend of 3906-B 2x hook tie in tail of two goose biots and tie in body material of black chenille bring to midpoint point of the size hook. Tie in wing case, of black goose or duck quill. Dub in thorax material of yellow or chartreuse dubbing. Tie in black saddle hackle for legs wrap over thorax or tie under hook eye. Bring wing case over tie off and whip finish.