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Stewart’s Killer Bug Trout Fly

Steward's Killer Bug has simple ingredients that make it easy to tie
Steward’s Killer Bug has simple ingredients that make it easy to tie

Chris Stewart’s Killer Bug is an effective nymph pattern that’s easy to tie and I’ve had good luck with it on Tenkara Rods and a traditional fly rod on New England streams and rivers. Many fisherman cite the Killer Bug as their most successful fly, so it’s a good addition for your fly box.

The Killer Bug is also featured in Simple Flies: 52 Easy To Tie Patterns That Catch Fish, a great book that provides easy-to-follow recipes for highly productive trout flies and step by step instructions to get started and refine your skills. I own a lot of fly tying books and find myself coming back to it every time I want to expand my repertoire of fly patterns.

In the course of tying flies, I’ve modified the materials and personalized the way I tie many of the flies I use. I don’t always have the same materials called for in a pattern and have to substitute others or I have to modify the technique into a sequence of steps that I have the skills to tie.

What follows are some of the ways I’ve adapted the Killer Bug that you may find helpful.

The Killer Bug is a pattern invented by Englishman, Frank Sawyer who tied it with Chadwick’s 477, a colored yarn, no longer available, which was supposedly irresistible to trout. Chris Stewart, a well-known Tenkara fisherman and author of the TenkaraBum website, tracked down a source of yarn to replace Chadwick’s 477, and the rest is history.

I can’t actually remember how I figured out that this yarn is Jamieson’s Shetland Spindrift Oyster 290, but it’s the yarn used in my Killer Bug. You can buy a lifetime supply from for $6.40. Chris also sells it (at least I think it’s the yarn he uses) in the one fly tying kits he sell on his website. I got started tying flies with them and the rest is history. They’re really good…and assume minimal fly tying knowledge and tools to get started.

The Killer Bug variant I tie below is sometimes called a Utah Killer Bug, because it uses a pinker yarn than Chadwick’s 477. You’ll also see it referred to as the Crane Fly Larva. I have some youtube links at the bottom of the post that illustrate different ways to tie the pattern.

The Killer Bug only requires a few components to tie which makes it a good fly for beginner tiers.

  • Hook size #12-18 (Daiichi 1560 #12, for example)
  • Wire: copper, lead-free wire, hobby wire (whatever scraps you have sitting around)
  • Oyster 290 Jamieson’s Shetland Spindrift yarn
  • Pink thread (Uni-Thread 6/0W, for example)

Start by wrapping your thread down to the base and coming back to the head.

Wrap thread down to the bend and bring it back to the head
Wrap thread down to the bend and bring it back to the head.

Next tie in some wire to help sink the fly. The wire doesn’t show in the final fly, so I tie in whatever scraps I have sitting around, including lead-free wire, hobby wire (inexpensive, found at hobby shops), or copper. While the yarn will absorb water and get heavier, adding weight will help get the fly down immediately and in front of the trout holding at the bottom of the stream bed.

Take 1-3 lengths with the wire depending its weight and thickness
Take 1-3 lengths with the wire depending its weight and thickness. Two lengths of copper shown here.

Wind the wire up the hook in touching wraps and helicopter the end off to avoid leaving a tag. For very thin copper, you may want to go up the hook and back to add more weight, as I’ve done above. After adding wire, I like to cover it with thread to lock the wire in place and neaten the foundation up. I then add in a half hitch to keep it together for the next phase of construction.

Wrap the wire with thread and add a half hitch
Wrap the wire with thread and add a half hitch.

The Shetland Spindrift yarn has a lot of spring in it and can be difficult to keep wrapped on a hook before you whip-finish the pattern. I like to “relax” it by pulling it apart into it two separate strands. You can also just use one strand for smaller hook sizes. I cut off about 12″ inches from my ball of yarn to work with and pull it apart.

Pull apart the yarn into two strands
Pull apart the yarn into two strands.

Tie the tips of the two strands to the fly, leaving the thread at the bend end. Then wrap the yarn strands around the bobbin thread. There’s no need to interleave them: just wrap them around the thread to create a rope. This hides the thread in the yarn as you wrap up the hook and secures it to the hook. The rope-like texture helps to mimic ribbing, much like wrapping wire around the outside of a dubbed fly.

Wrap the yarn around the thread to form a rope
Wrap the yarn around the thread to form a rope.

Wrap the rope up the hook and back, depending on the thickness and size bug you want. Avoid getting to the yarn rope too close to the hook eye, to keep it easy to thread with your tippet stream-side. I like to do two passes with the yarn: one up to the head and one back to the bend. At the bend, separate the yarn rope from the thread. Secure the yarn on the hook with a few wraps and snip off the rest.

Making a whip-finish at the bend end can be a bit difficult, so I use an extended whip finisher. This is nice tool for tying many flies, when you want to make a whip finish at the the other end of the hook.

An extended whip finisher (bottom) is very helpful for tying off flies near the bend
An extended whip finisher (bottom) is very helpful for tying off flies near the bend.

Whip finish the Killer Bug and that’s all there is to tying this fly. With a little practice, you can tie this fly in a few minutes. I make them up in #12 and #14 sizes on longer nymph and curved hooks.

Whip Finish
Whip Finish – Killer Bug

Here are a few videos that show other ways to tie the Killer Bug and its variants, that may give you ideas about how to personalize the way you tie it given the materials and tools you have at hand. Simple to tie. Fun to fish.

Written 2017.

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  1. When I first glanced at this, I hadn’t finished my coffee and misread the title into a post on bug repellant. If I made one of those things, it would probably qualify as trout repellant, however, I’d gladly eat whatever you caught with yours!

    • I have found that obsessing about tying trout flies is a lot more relaxing than obsessing about politics. It’s now my number one prescription for election and news media stress, no matter what your political beliefs are. There’s something mentally cleansing about imitating bugs with thread, wire, and feathers.

  2. I can attest to the efficacy of the UKB. It’s simple to tie, cheap, and trout love it.

  3. Chris from TenkeraBum is amazing. Tons of great information and 1 on 1 help. I purchased my Suntech GM Suikei Keiryu Special 39 from him and I could not be happier. The Killer Bug is an amazing fly. My favorite fly to date, but I’m a Tenkara amateur.

  4. Yes The Killer Bug is fantastic ..I use them as well as make them my self….I spend the time making flys
    during the snow months here in Ohio..good pass time hobby…Oldmiser

  5. I’ve tied and fished the exact same fly only on a much bigger or longer shanked hook, up to 6s and 4s, which is closer in size to the Crane fly larva that I’ve seen. They can get pretty big. I’ve fished them great success out west. I don’t know if they inhabit eastern/mid-western streams though, but fish are always eating and spitting out things that float by. Vary the colors too, from dark brown to olive to tan. And vary the weighting too. Perfect fly, easy, cheap to tie and effective!

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