My best guess would be a PMD. As soon as you add a more robust wing you are getting into creating your own version, using your own colors of materials, etc.
Enjoy.
Larry ---sagefisher---
Looks like a No Hackle fly
http://www.west-fly-fishing.com/fly-pattern-recipe/dry/nohackle.shtml
Nope, neither of you wins the golden tier award. It is a style of Mayfly, but not a no-hackle. There is a single wing, tied into a spinner-like body, hackle out to the sides, and it is a very fine feather, fine enough that you can actually see through it. Might be a CDCfeather.
Wally wing?
Wow, I think that might be it. Only WW's are made with hen, right? This feather has a teensy tiny back to it. But I think we're gaining on it.
I remember those now, and that is still not my wing. It is a single feather, tied down on top at a short distance from the end of the feather, then bent around and the filaments of the feather tied down at the same point as the original tie down.
Could we get a better look at it?
A bigger image with a contrasting background (white, black or light green paper) would help us solve your mystery.
Will try to get a better pic.