This is one of the most successful patterns I have ever used and tied. I have been using it since the late 1970's.
If you can find a copy of "Fly Tyer Magazine" dated August 1981 There is an article written by the creator "Nathan Winter Streeter" that explains the way the fly was originally tied. It also says he created for the North Platte River in Wyoming. It was designed for the Dobsonfly and not as a stonefly as is generally believed . I got this from a personal conversation with Mr Steeter himself. But as he also said it works as "juicy morsel" especially for Brown trout. A very interesting article. Just thought I would pass it on.
Nice Tie and correctly tied per the original.