Dean Reiner has been tying flies with his daughter Dandy for decades. Dean started Hatch Finders Fly Shop in Livingston ages ago and ties many of the fly tying patterns he sells in the shop to clients who come out to the Yellowstone River fly fishing for trout and other species. He’s an expert on how to tie a fly and from beginner fly tying to expert level patterns.
This dry fly pattern is a bit unique in that the fly is meant to sit in an upside down position on the water.
https://www.hatchfinders.com/ is now owned by Dean’s daughter and fly tier in her own right, Dandy Reiner. Check out her patterns here.

RECIPE
Hook: Standard dry, sizes 10-14
Thread: Ultra Thread, 70 or 140, Black
Hackle: Whiting Farm, Brown
Tail: Moose
Wing: TroutHunter CDC, Medium Dun