From Mark Sturtevant:

Mark Sturtevant: Have the right flies for fall fishing
Fishing in the autumn requires making sure you have a fly box stuffed with the correct flies.

Tying the Fluttering Black Stonefly – Dakota Angler & Outfitter – Black Hills Fly Fishing
The Fluttering Black Stonefly pattern features a unique spit CDC wing technique that mimics the fluttering wings of the natural.

