The Pocono Mountains of northeastern Pennsylvania are veined with trout streams that used to be far more celebrated than they are now. It was in that region in the 1930s that local angler and tier Hiram Brobst first tied this somewhat fussy pattern, supposedly to imitate the caddisflies on Brodhead Creek, and it seems to share some features with classic British sedge patterns. This is a great fly to try when trout are rising to caddisflies in flat water or when they are being selective.
In this great video from Tightline Productions, Tim Flagler offers his method for creating this useful pattern. The key is in how you deal with the matched mallard-flank slips used for the wings. Tim has a neat trick for matching the pair, using a bodkin, and he offers a clear explanation of how to attach the wings to the hook so the lie perfectly.
Hook: 1X-long dry-fly hook (e.g. Dai-Riki #300), size 14.
Thread: Black, 6/0 or 70 denier.
Abdomen hackle: Grizzly.
Abdomen: Olive Superfine dry-fly dubbing.
Underwing: Wood-duck flank feather fibers.
Wings: Mallard primary-feather slips.
Hackle: Brown or ginger.
Thorax/head: Tying thead.