This is a great stone fly nymph pattern that is really efficient and effective tie. The tail is made of 2 biots (thanks to Dallas for biots and the pattern). Tie in your thread at the eye and wrap it down the hook shank to the bend of the hook. Tie in the biots. It takes a bit of trial and error to get them to sit right, but once you get the method down you'll get them in no problem.
Second tie in thin copper wire or mono (in front) of the biots.
Once the biots are tied in, I start dubbing with all purpose natural rabbit dubbing. I've tried a couple of the synthetics but I didn't like the way they look. They didn't have the buggy/spikey look. The natural rabbit dubbing works well for this fly and most any other pattern I've used it on.
As you get closer to the hook eye, build up the body and stop dubbing about a 1/4 inch from the eye of the hook (maybe a little more). Let the spool hang.
Go back to the copper wire and wrap probably 4-5 wraps evenly spaced. Don't cynch them down though, it'll kill the buggy look. Make the wraps tight, but not so tight that they cut through the dubbing and get buried.
Do a couple of wraps with the thread to tie in the copper and cut and leftover copper off (I usually just wrap it around the shank for a little extra weight).
Ok, next, the wing case. for the fly I tied for this swap I took a turkey tail feather and treated it with flexcoat (you could easily use a pheasant tail too). Once it's dry I strip off about an 1/8 inch section of the coated feather.
Tie it in where you stopped the dubbing and wrap it 4 or 5 times to make sure it's in good. Once the turkey is tied in, it should point out towards the bend of the hook. Continue dubbing towards the eye and stop just short of the eye (enought to tie in your wraps for the knot). Note: when I am dubbing in this thorax section, I add a bit more dubbing than when I did the abdomen section and I leave it looser.
Once the dubbing is finished and your spool is near the hookeye, Pull the tail feather/wing case over the dubbing and tied the feather in with 2 or 3 wraps...snip the remaining feather off, and then continue wrapping and and a few half hitches in.
That should be it. You can add some head cement.
Once you've got it off the vise, take your bobkin or a hook eye and fluff up the fly. Sorry for the long read...try it out and post a pic.
PK