Tim: This is a size 16 Iris Caddis. The pattern comes from Craig Mathews at Blue Ribbon Flies in West Yellowstone and many believe it to be one of the most effective caddis emerger patterns ever developed.
Tim: Matt Grobert, author, fly tying instructor and host of the blog "Caddis Chronicles" is going to demonstrate how he ties an Iris Caddis.
Matt: Begin by flattening the barb on a TMC 100 size 16 hook. The finished fly does a very good job of imitating the hydrophsyche caddis which ranges in size from about a 14 down to an 18 so those sizes are appropriate as well.
Start your thread a little ways behind the hook eye, here Danville 6/0 (oh) in olive, and wind back to midway between the point and the barb.
To form the pupal shuck of the fly, snip off about an inch long piece of amber Zelon from a strand. Zelon is a very specific material and is available exclusively through Blue Ribbon Flies and Umpqua. Secure the segment to the top of the hook with a few nice tight wraps. Continue to take wraps down the bend of the hook a ways so the shuck points slightly downward as it does with naturals. Take wraps up toward the eye to tie the remainder of the zelon down to the top of the hook shank and create a uniform foundation for the body of the fly. Clip the Zelon off short, about a hook gap length, to complete the pupal shuck.
For the body of the fly, I like using a zelon and rabbit mix in hydrophsyche tan from Blue Ribbon, olive also works well. Create a tapered dubbing noodle on your tying thread. With the noodle complete, you can then begin taking wraps to form the body of the fly.
Try to make a nice tapered body but keep the overall appearance rough. The idea is to make the body look like a caddis trying to wriggle free from its pupal shuck. The body should end rather abruptly 2/3rds of the way up the hook shank.
Now fold over the end of a length of clear crinkled Zelon to create a loop. Place the loop flat over the top of the fly and take a wrap to hold it in place. The back edge of the loop should extend just to the base of the tail. Pull straight up with your tying thread to lock it down. This loop represents both the emerging wings and the gaseous bubble caddis generate to raise themselves through the water column to the surface.
Snip the excess Zelon off at an angle close to the hook and then bind it down and cover the butt ends to form a nice foundation for the thorax of the fly.
For the thorax, I'm using regular Hareline hare's ear dubbing. By pulling the fibers apart horizontally and then putting the two piles back together I'm roughly aligning the fibers in the same direction. In the textile industry this process is called carding. While holding onto the pile apply a thin film of real sticky wax to about two inches of the tying thread.
Lightly apply small sheets of fibers so they adhere to the wax. This is referred to as "touch dubbing". Don't worry if the hairs and fibers aren't perfectly uniform on the thread, you just don't want to clump it on too heavy. Keeping the dubbing noodle and your tying thread fairly short here will make the next step in the process easier by giving you more control.
Starting back near the wing, begin wrapping your thread and dubbing forward folding the hair and fibers back as you go to make a nice buggy-looking thorax. And yes, it really should look this raggedy. Wet your fingertips and pull the dubbing back to get a few clean wraps behind the eye.
Finally, you can whip finish and snip or cut your tying thread free.