Hook: Standard Nymph Hook
Body: Blended Light Hare’s Ear dubbing, such as Hareline Hare’s Ear Color, you can also add a bit of antron to the blend
Thread: Tan or Gray
Tying Notes: Make sure to use a dubbing that has a nice mix of underfur and guard hairs, to get that “buggy” look. I tie most of these heavily weighted. I do leave some unweighted for those occasions when I want to drift it in shallow or slow moving water.
General Notes:This pattern was originated by Central Pennsylvania Fly Fishing star Walt Young. I think it is taken by the trout as many different things (sow-bugs, scuds, crane-fly larvae, caddis larvae). That general effectiveness is the reason it is a staple in many fly-boxes. Tie these up in size 10 through 16. make sure you fish it dead-drifting right along the bottom.
I use Walt’s Worm most often as a sow-bug imitation on Pennsylvania’s Spring Creek. There are more elaborate imitations available of course – but Walt’s Worm has caught more fish for me on Spring Creek than anything else.