This fly will only be used once or twice a year, but when the trout are taking tiny insects off the surface, this fly will succeed where others won't.
Trim the Ethafoam to shape and secure to the hook about 1/3 down the hookshank from the eye.
Catch in a red cock hackle to the secured area of Ethafoam and wind the hackle a couple of times.
Secure the hackle, cut away excess and whip finish.