WD-40 Midge Pupa

Hook:   TMC 2487 or equivalent in appropriate size, usually #16-20 with #18 being a good starting size. If you don't have this hook then use a 2x-short hook to give a wide hooking gap relative to the hook length.
Thread: the color of the body of the midge - brown, olive, red. etc
Tail:   Wood duck flank feathers, hence the WD of WD-40.
Body:   Abdomen is formed from the tying thread, coarse dubbing for the thorax of the pupa - Hare's ear dubbing is about right. You can also use peacock herl. I use a hare's ear/Antron blend.

1) Start the tread on the hook and wind it to the rear of the hook. Tie in about 5 wood duck barbs as the tail of the fly. Wrap over the wood duck feathers all the way to the head of the fly, forming the body of the fly with the tread.
2) Pull the butt ends of the wood duck feathers back over the body so that they are now directed back towards the tail. Wrap the thread back towards the back of the fly enough for the thorax, about 1/4 to 1/3 length of the hook.
3) Dub the thorax or tie in the peacock herl and wrap to the eye of the hook leaving enough room to tie off the head. Now bring the wood duck feathers back over the top of the dubbed thorax towards the eye of the hook and wrap dowm to form a "wing case". Cut off the wood duck feathers and whip finish the head of the fly.

This is a popular fly on the San Juan in New Mexico. I first learned of it on this list from Henry Kennemoto, and found it to be a common fly when I fished the San juan. Fish the WD-40 dead drift as a midge pupa with a split shot and strike indicator. Let it swing at the end of the drift and rise up towards the surface as a natural would rise. Many of the strikes will come at this time. After the swing and rise, slowly bring the fly back in a hand twist retreive and this will also bring an occasional strike. Once the trout are at the surface feeding on midges in the foam line, take the weight off the leader and cast into the foam line and try a slow retrieve. You can also use a large dry fly as the indicator, and tie the WD-40 as a trailer off of the hook of the dry.