That would be a
Pheasant Tail Mahogany Dun Emerger with 90 Degree Hackling.
There have been lots of cutthroat trout taking emergers on my home water recently, but there is no way to get into the part of the crick where they have been feeding to sample what is in the drift. Since there is reportedly a hatch of mahogany duns on this river this time of year, I decided to treat the trout to a new version of one of their staples.
The tail / shuck is the tip ends of the pheasant tail fibers. After tying them in as the tail / shuck and wrapping the tyng thread forward to the thorax area, the bundle of PT fibers is twisted and then wrapped forward in touching turns to form the abdomen.
Haven’t had any problem with the hackle unraveling after just wrapping it down the post and then around the shank before tying it off. I’ve used the same approach for the 9DH on Duck’s Green Drake and Duck’s BWO, and a couple earlier patterns, without any problems with the hackling on any of those flies.
I don’t see any problem doing what you are suggesting, but it isn’t necessary based on my experience with these flies to date.