I happened upon a gray mayfly [dun, just hatched] today while fishing near Stockton NJ, and for the life of me cannot seem to find an exact match in any of my books. I am going to describe it, maybe someone [with more entomology experience] could help me out.
It was a standard length # 12 dry fly hook in length, but I would tye it in a #14, wings were very dark gray, body was adams gray with darker gray segmentation, 2 tails and it had that quill gordon shaped head [kind of triangular with small eyes, not big bulbus ones]
He was quite handsome, and friendly, and fortunately for me, his younger siblings were keeping the local trout population fed, as I had the best day nymphing I ever had. Thanks, CJ