Caddis fly larva are a favorite food of trout just about everywhere and patterns to imitate them range from mildly suggestive to hyper-realistic. I’ve been using the same fairly simple suggestive pattern, in sizes 14 and 16, in both green and a rusty brown for years. In trying to change it up a bit for the coming season, I actually simplified things by removing the wire ribbing and changing my dubbing technique to produce what I hope will be a more effective fly.
For a hook, I’m going to use an Orvis Tactical Barbless Czech Nymph hook in a size 12 to help illustrate some of the thread techniques but would recommend using a size 14 or a 16. Start by getting the hook firmly secured in your tying vise.
I’m going to use heavier thread, again, for demonstration purposes, here, UTC 140 in yellow olive. 70 Denier will also work just fine. Understanding how UTC thread can be either corded or flattened is important for tying this pattern. To cord the thread up, give your bobbin a clockwise spin. As you can see, this produces a corded, rope-like thread that creates thick, segmented wraps. By spinning the bobbin counterclockwise and un-cording the thread, you end up with flatter, smoother floss-like wraps. To ensure your thread has the correct amount of twist at the start of the fly, pull 10 inches or so out from the nozzle of the bobbin, then squeeze the thread between your fingertips and pull it through your fingertips to flatten it out. It doesn’t have to be completely flat, you just want to make sure it’s not really twisted up. You can then return the thread to the spool to minimize waste.
Start your thread on the hook shank above the point and take wraps rearward before snipping or breaking off the tag. Continue taking thread wraps down into the bend of the hook. You can see these wraps are fairly flat and smooth.
I’m going to use light olive Australian possum dubbing for the abdomen of the fly. Get hold of an ample pinch and set it aside for safekeeping. Give your bobbin a counterclockwise spin to ensure the thread is completely flat and untwisted. Running a dubbing needle behind it really helps to spread the fibers out, as you can see here. Use that same dubbing needle to split the flattened thread down the middle and insert the index finger of your left hand between the two strands.
Place the dubbing in your bobbin hand and pinch it tightly. Pinch and pull with your right hand to get the fibers oriented roughly perpendicular to the tying thread and insert them between the two strands. Keep doing this until you’ve built up a 4 inch length of thin dubbing between the split thread. Remove your index finger from between the strands. Give your bobbin a really good clockwise spin to cord up the thread. The more you spin, the tighter the dubbing will be wound and trapped.
Start taking wraps around the hook shank with the dubbing noodle so it begins deep down into the bend. Keep making touching wraps up the hook shank to create the body of the fly. Ideally, you want to end about 3 eye lengths behind the hook eye. It should look something like this.
For the darker head, I’m also going to use Australian possum, this time a dark brown. Again, get hold of a small pinch and set it aside. Use the same procedure as before, giving the bobbin a counterclockwise spin to uncord the thread and flatten it. This will then allow you to split it with a dubbing needle. Here, you don’t need quite as much dubbing material, as before. Spin the bobbin clockwise to twist the thread and fur into a tight little dubbing rope. Once done, you can use the rope to build up a bushy thorax and head on the fly. It’s very important at this point to give the thread a counterclockwise spin to uncord it, otherwise, you may end up with a tremendous knot when you go to whip finish. With even moderately flattened thread, it shouldn’t be a problem. Do a 4 or 5 turn whip finish and then snip or cut your tying thread free.
Now comes the fun part. Tease all the fur upward with your fingertips like so. Then, reach in with your tying scissors and cut the fur off to form a roughly tapered body. Now push the remaining fur downward and give it a little trim. You do want to leave these fibers a bit long to imitate the larva’s legs and gills. It should look something like this. Notice how the dubbing method kind of hints at segmentation. I really think this pattern will be a winner and hopefully out-fish it’s predecessor, but only time and warmer weather will tell.