This fly is called JC's Electric Caddis Pupa. It's originator, John Collins, is well known in northeast fly fishing and tying circles. He's a regular tier at many of the region's shows and is a member of the Regal Vise Pro staff. Although he learned to tie in the traditional Catskill style, it's his innovative patterns such as this Caddis Pupa that have really gained him recognition.
John starts with a size 12 Daiichi 1150 hook. For thread, fluorescent green 70 Denier Ultra thread. Start your thread on the hook shank leaving an eye length space behind the eye. Take wraps deep into the bend and then bring your thread back to about the 2/3rds point on the hook.
For the abdomen of the fly, cut free from the spool a 6 inch long piece of fluorescent chartreuse Ultra wire in the small size. Then, cut about the same length piece of fluorescent chartreuse micro-sized stretch tubing. Insert the wire into the stretch tubing and then twist the tubing while you continue to feed the wire in. Leave about 1/4 inch of the wire exposed. Take a few thread wraps, first around just the wire and then the wire and the tubing. Continue taking wraps rearward to where your thread ends and then back to the hook point.
Dub a noodle of fluorescent green Antron blend and take wraps to form a plump football-shaped underbody for the fly. Then take thread wraps to cover it well. John likes to throw in a half hitch at this point.
Now, pull the wire tubing combo tight to stretch and flatten out the tubing. Keep this pressure on as you take 3 adjacent wraps up the hook shank. You can then begin to gradually release the pressure. What this does is allows the tubing to expand to further enhance the abdomen's football shape. Once you get to the hook point begin to put the pressure back on for 2 or 3 wraps to once again thin out the tubing. Take a few good tight thread wraps to bind the wire and tubing down and then snip it off close with nippers as it will dull good tying scissors. Take a few more thread wraps to really lock everything in place.
Snip about an inch long piece of black swiss straw and completely unfold it. Tear the piece in half lengthwise then fold one of the pieces in half, also lengthwise. Then snip that piece in half. Sandwich this folded over piece in a caddis wing burner and then, with a lighter, burn off the excess. You should be left with 2 similar pieces that will be used as wing buds.
Tie one of the wing buds on the far side of the hook so it extends rearward but doesn't cover the entire abdomen. Do the same on the near side. As you can see here, John's in the construction business. With the wing buds secured, pull the butts back and snip them off close. You can then take thread wraps to cover them up. Do a light whip finish to secure your tying thread and then snip it off close.
Now load a bobbin with tan thread, here John's using Benecchi 12/0. Start the thread behind the hook eye and then take wraps to cover up most of the green. Using tan antron blend dubbing, create a small noodle on your tying thread and wrap it from the base of the wing buds all the way up to just behind the hook eye.
Strip about 6 or so pheasant tail fibers free from the stem. Keeping the tips aligned, secure them to the underside of the hook shank then pull them to create legs that extend to the back of the hook. Take a few more wraps of tying thread to secure the fibers then fold the butts back and take a few more wraps to really lock them in. You can then lift the butts and snip them off close.
Although not absolutely essential for this next part, a drop of Clear Care Goo Hydro will really help to increase the durability of the fly's mallard flank fiber antennae. Simply drag the fibers through the goo, wipe off the excess and then give them a good shot of ultra-violet light. It's amazing how strong the fibers become using this technique. Tie them in one at a time, in a splayed position on top of the hook shank. The fibers should reach just beyond the hook bend. Lift the butt ends and snip them off close. Then take thread wraps to secure the antennae and build up a head on the fly.
Give it a good solid 5 or 6 turn whip finish and snip your tying thread free. Add a coating of head cement to the thread wraps if you like and your JC's Electric Caddis Pupa is complete. Don't be afraid to mess around with different colors to match the naturals.