There are a lot of flat aquatic insects, and hooks are not flat. To imitate these morsels, a little stainless wire is needed.
Hook: Mustad 9671 2XL wet fly hook 6 -10
Body: Wireframe, floss
Legs: Wet grade hackle
Epoxy
The hardest part of making this fly is turning out identical wireframes from stainless wire. There is no real trick other than paying attention to detail. They should be a soft cornered bullet shape in profile. Make a bunch before attempting to tye any.
Create a firm foundation and then tie in the frame and the floss at the tail Tie in a hackle lying flat along the length of the shaft, cant toward the tail. Wrap the floss forward, making sure that the hackle protrudes between each wrap. This is a careful operation and it makes a great deal of difference in the final product. Tie off the floss at the eye and finish with a wrap know. Carefully apply 5 minute epoxy to the floss on the wireframe, top and bottom, being sure not to get the hackle soaked. Allow to set. Trim the hackle to represent legs and gills.
Being flat, this fly tends to glide on the sink, the hackle supplying a motion along the way. Be prepared for hits on the descent. These act very muvh like dragonfly nymphs, and most species of fish love them. Being epoxied, this is a very durable fly with a quick sink rate. It needs a bug taper with a strike indicator to work effectively.