I started tying this fly several years ago without knowing how it would ‘work out’. I’ve been pleasantly surprised as it has been effective. I’ve caught many fish including a nice Brown up Cedar Run several years ago and used it in the Fall catching a few Rainbows and Browns out in Pine. Shortly after I tied the first few off the vice someone said to me that it looked like an ‘ISO’ as in Isonychia Bicolor. But out in Michigan I also fished it when a Brown Drake was ‘in season’ and caught fish with it.
So I’ve always thought of this fly as my ‘Iso – Brown Drake’ …. thing! Thus, for your observation, the Iso-Brown Drake, Mahogany Dun, Slate Drake……. fly!

Standard parachute post dry fly tie. Has a wire rib on it too and a little dubbing in the thorax area. Pheasant tail, tail; Pheasant tail body, Gold wire Ribbing; Deer hair post, 1-Brown and 1 Grizzly hackle, Superfine Rusty Brown dubbing Thorax – Brown thread- Veevus 10/0.