The coffin fly is the spinner of the Eastern Green Drake and is fished mainly at night. The deer body hair adds a buoyancy that you can't get from many materials while keeping a slender profile. Add to that, it does not hold much water, so there is little worry at night about the floating ability of your fly.

Material List:

Hook: MFC 7050 #6
Tail: Moose Body Hair
Body: White Deer Body Hair
Wings: White Poly Yarn
Thorax: Black Superfine Dubbing
Hackle: Black/Dun Grizzly (Trimmed)