May I share a pattern here that works well for a troubling Stonefly!
I tie these in sizes 8-12, using a heavy wire hook, typically a (2x or 3x lg, nymph hook, for a bit more wt.). Body ins "awesome possum", tied in good taper back to front, working towards what Donald described as "big and fuzzy". As a rib I step a bit out of tradition, but like the effects of using a Midge size Diamond Braid", in a contrasting color! Finish with 2-3 turns of hen hackle, to compliment the body. The Midge size braid works well with this size of hook.... who would of thought....
My all time fav for those little clinger type stone flies!
Black Body, with a light blue rib, black hen hackle!
In tying, I focus on drawing the rib deep into the dubbing, allowing it to highlight more then accent, if that makes sense! Second Fav color is a "golden olive body with a lemon-yellow rib, with a ginger hackle!
Not quite traditional materials but it addresses the hatch! A great fly to fish along the bolder, rock bluff streams, fast water, the type of places that these little critters could get washed a drift.
FliTrap