Killer Bug

Frank Sawyer's Killer Bug is a great fly. Since I first tied this fly 18 years ago it has been my most productive fly by far. What makes it even better is that it is very easy to tie and uses inexpensive materials (at least the way I tie it), just some knitting yarn, some copper wire and a Prismacolor marker.

The Grayling Killer Bug, as I believe it was originally called, was developed in the 1930s by Frank Sawyer, the same man who developed the pheasant tail nymph. At that time, Sawyer worked as a river keeper on the river Avon. As part of his duties, he was to rid the river of grayling. According to his grandson, Nick Sawyer, who used to run Sawyer Nymphs, Ltd. in the UK, the fly that Frank developed (which imitates the gammarus pulex - what we call a scud) was more effective than netting or electro-fishing. I can believe it.

I often find myself wondering, "why do I fish anything else?" Variety, I guess. Nothing I've found outperforms it.

I guess my comment above about inexpensive materials should be explained a bit, in that Sawyer tied his fly with a yarn that is no longer produced - Chadwick's 477. That yarn is now one of those almost unobtainable fly-tying materials that have achieve a near-mythical status - I would say more than polar bear hair or seal fur, more than the urine-stained fox fur for the Hendrickson (though maybe not more than the ram's scrotal hair that is, well, indispensable for the Tups Indispensable). Chadwick's 477 hasn't been produced for over 50 years now, and when the rare card is auctioned on eBay, it goes for over $100.

In his book Nymphs and the Trout, Sawyer wrote "The colour of this bug changes completely when it is wet and I feel sure it is this, that causes its attraction for so many kinds of fish. Though I have constructed these bugs with many other colours of wool, none have been so effective." Chadwick's 477 was a fawn color, kind of a greyish brown, but it had red fibers running through it. That was the key. When the yarn was wet, the red fibers in the yarn gave the Killer Bug a reddish brown or pinkish tan hue.

Although substitutes are sold in the UK as Killer Bug Yarn, and some are quite close when to the actual color of Chadwicks 477 (when both yarns are dry), none that I have been able to find have any red fibers or show the pinkish-tan color when wet.

I've also read comments on various forums that suggest that any yarn will work. I'm convinced the people who say that do so only because they haven't tried one that does turn a pinkish tan. After all, Sawyer should know. He specifically wrote that he tried many other colors and none were as effective.

I think Sawyer was absolutely correct when he said the successful attraction is due to the color. Yes, bugs tied with other colors of yarn will catch fish. No, they probably won't catch as many fish.

I started fishing Killer Bugs in 2008. I looked extensively for a yarn that had the "fawn" color that people familiar with the original Chadwicks 477 had described, and also had red fibers running through it to give it the pinkish hue when wet. I found none.

The yarn I settled on then (and still use today) is a Jamieson's Shetland Spindrift yarn. The color I use is Sand (not Oyster, which the Tenkara Guides of Salt Lake City chose for their Utah Killer Bug) Sand is an off-white, too light even to be called "oatmeal." But it does have the red fibers running through it. To give it the requisite tan color, I use an artist's Prismacolor marker. The color of the marker is also "Sand." Pure coincidence.  I suspect, but do not know, that the Tenkara Guides didn't want to mess with a marker (or perhaps the yarn shop didn't have Sand in stock at the time or perhaps they just liked the color of wet Oyster).

The resulting fly (Sand yarn and Sand marker) turns a definite pinkish tan when wet and is a very close imitation to the scuds that have a pinkish hue. I have finally gotten a very small sample of the original Chadwicks 477, and the Sand marker I use is just a little too tan but the trout don't seem to care. If they don't why should I?

It seems the Prismacolor Sand color, like the Chadwicks 477 yarn, is extremely hard to find. Last I checked, it was included in a 72 color set, but not was not available individually. My marker is still usable so I have not sought out a suitable replacement. Look for a light tan, ideally with a slight grayish hue.

The fly is tied with copper wire - no tying thread. The copper wire provides a little bit of extra weight, but not nearly as much as a lead underbody or even a bead head. (With a soft rod and a light line, you can still tell it's a weighted fly, though.)

Sawyer wrote in his book that the color of the wire was not important, but that when he wrote the book he normally used red - which probably was a varnished copper wire that had a slightly reddish brown color. The photos I have seen of the authentic, original Killer Bugs did not show bright red wire. I think by "red" Sawyer meant the reddish brown color of the varnished wire that was used in (probably scavenged from) transformers and electromagnets. When I was a kid I used some varnished wire to make a chrystal radio. It was reddish brown, not really red. 

Scuds can swim - fast - and for a time I fished the killer bug with quick tugs to mimic a scud's swimming action. After having fished with a truly Hi-Vis Fluorocarbon level line, and seeing strikes that I'm sure I wasn't seeing before, I decided a dead-drift approach was better.

I don't know that giving action to the fly with quick tugs produces more strikes, but it certainly causes your line to bounce around, and if your line is bouncing around it is very hard to see the subtle strikes. Truly, some strikes are so subtle that they move the line much less than the motion caused by even a gentle pulsing action.

Also, when the line is bouncing, there are times that it is slack, and a fish can spit out the fly long before you can take the slack out of the line with your next tug.

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Killer Bug Step by Step

I am more than a little embarrased to confess that I have been tying the Killer Bug wrong for 18 years (using just one layer of copper wire rather than his two layers). I may have initially tried two layers and decided that one was easier, or I may never have seen Sawyer's own instructions for how to tie the fly. I just don't remember.

1. Because copper wire slips pretty easily when wrapped, I start by just touching the hook shank with super glue. I find the brush applicator works better. (Needless to say, Frank Sawywer did not have super glue in the 1930's when he developed the fly. Also, if you hold the end of the wire at the bend until the fly is finished, the copper wire doesn't slip.)

2. Start the copper wire at the bend, wrapping forward to the eye in tight touching turns and then back to the bend, again in tight touching turns. (This is a correction from my initial instruction to start the wire at the hook eye.)

3. Start the yarn like you would start thread behind the hook eye. This photo was taken just before clipping off the tag end. Wrap to the bend, back to the eye and then back again to the bend. You need to wrap tightly so the yarn doesn't start sliding around after a few fish. I try to wrap the yarn, which is two ply, so the the plies lay side by side as I am wrapping.  Some people twist the yarn so that it resembles a cord, which does produce a bit of a segmented look. I find the twisted yarn harder to control and have not noticed any improvement in catch rate. Photos of authentic, original Killer Bugs pretty clearly show that Sawyer himself did not twist the yarn.

4. When you get to the bend, trap the yarn with one wrap of wire. I then do a five turn whip finish with the wire (four turns if tying on a size 14 scud hook). Tighten the wire very gently and smoothly or it will break. When it is tightened, then break off the wire tag end and then clip the yarn tag end.

I have always done a whip finish by hand rather than with a whip finish tool. For those who prefer to use a whip finish tool, I'll pass along a tip I received from Kirk A: use a whip finish tool designed for salmon flies, which sounds like it might be larger.

Sawyer just did four wraps with the copper wire to trap the yarn and finish the fly. He did not do a whip finish or half hitches and did not mention using cement to glue the wraps. He also did not mention Killer bugs ever coming apart. 

5. While the fly is still in the vise, I color it thoroughly with the Sand Prismacolor marker*. It looks brown initially, but as the color sinks in, the fly will take on a pinkish tan look, which intensifies when the fly is wet. Coloring it roughly with the marker also raises loose fibers, which create a bit of a halo effect, and gives the impression legs.

*You may have to find a substitute because it is now very hard to find the Sand Prismacolor Art Markers. Alternatively, you could use Jamieson's Shetland Spindrift Oyster yarn instead of Sand and not use any marker.

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Utah Killer Bug

The Utah Killer Bug is an adaptation made by the Tenkara Guides in Salt Lake City, UT. They say it was an attempt to simplify the tying process, settling on a yarn that does not require the Prismacolor marker, but watching a video of their actual tying sequence, with two bobbin holders (one for thread and one for wire) and yarn all hanging down from about the same half inch of hook shank, it looks much, much more complicated to me.

If you want to eliminate the marker, by all means use the Oyster yarn they chose but I would still follow Sawyer's tying sequence shown above. Truly, it is simpler and has been catching for 90 years now. Oyster is darker and quite a bit pinker than the Sand color I use for the Killer Bug. When wet, though, both yarns darken and both show a definite pinkish tan hue. The Prismacolor marker I use is not waterproof, so after a few uses, the yarn loses some of it's brown color and bugs tied with the two yarns end up looking somewhat similar.

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