Frank Sawyer’s Killer Bug is a very productive fly and is simple to tie, my favorite kind of general purpose fly to be combined with an RS2 in a two-fly rig.  It simply requires knitting yarn, some copper wire and a hook.  Frank Sawyer used to tie these flies without a vice, simply holding the hook in one hand and the material in the other.  This fly developed a reputation as a grayling killer bug, whereas his pheasant tail nymph was more often the one chosen for trout, but I have found that it works well on grayling, trout, and even Alaskan or Kokanee salmon.  His grandson, Nick Sawyer, is a special forces Captain in the Royal Services, also moonlights offering his grandfather’s Sawyer Nymphs.  The fly imitates the gammarus pulex or what we commonly refer to as a scud but also seems to be taken for an egg pattern in the smaller sizes or a crane fly larva.  

Frank Sawyer tied his fly with a yarn that is no longer produced – Chadwick’s 477, which he wife used for darning wool socks.  That yarn is now one of those legendary fly tying materials that has achieve a mythical status, along with polar bear hair, seal fur, and urine-stained fox fur.  Chadwick’s 477 hasn’t been produced for probably 40 years now and when the rare card is not handed down in someone’s will it sells at auction for over 100 quid.

Fortunately for those of us without ancestors with foresight, there are substitutes. Veniard “killer bug yarn” is one and Lureflash 477, both also difficult to find.  Chris Helm’s Whitetail Fly Tieing Supplies carries a “Chadwicks 477 Yarn” substitute that is marketed by Lathkill Fly Fishing in the UK.  I’ve also had success with rummaging through yarn and craft stores with my Frank Sawyer’s original killer bug and small strand of Chadwick’s yarn given to me by Nick many years ago.  Sawyer said, “The successful attraction of this pattern is due to the fact that the particular ‘darning wool’ used, completely changes colour when wet.” Chadwick’s 477 is a fawn color, kind of a greyish brown, but it has red fibers scattered through it, and when the yarn is wet, the red fibers gave the yarn a pinkish tan hue.

The Veniard yarn and the Lathkill yarn, remains more tan than pinkish when wet, so it is not as good as the Chadwick’s or Lureflash.  Any yarn may work, as many suggest, but I believe that the killer attraction of the original is due to the color.

Jamieson’s Shetland Spindrift in the Sand color can also be died with a Sand color  Prismacolor marking pen, and turns a definite pinkish tan when wet, is a very close imitation to the original but a bit too tan.

The fly is tied solely with copper wire and 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 beadhead. Sawyer used a varnished copper wire that had a slightly reddish brown color, but it seems you can’t get that color anymore. I use old telephone wires (the kind you use to connect the phone to the wall) separated for this purpose, which take on this reddish patina with age and exposure to the air.

A dead-drift approach is the usual technique, but fish can also take the fly as it swings to the surface and I know some who like to give the fly action with quick tugs, a technique I have found unnecessary.

Nick writes, “If only Chadwicks knew the trouble they had caused! Below are some facts:

Chadwicks ceased production of 477 in around 1965.  Frank did indeed have a substitute made by an American he met on the river bank. This same gentlemen still provides me with the substitute wool. It is the colour of the wool when wet which is important and this is affected by the colour and thickness of the copper wire beneath the wool. The colour of the wool is reasonably important but by far the most important element of the Killer Bug is the manner in which it is fished. I have tried many substitutes of suitable colour but the main problem has been the fibres rather than the colour – it is important to have the right thickness and the correct mix of natural to artificial fibres. I have no idea what the correct ratio should be, but high levels of artificial fibres make for a poor Killer Bug.

Here is a handy guide for Killer Bug fishermen:

1. Get the technique right – it is possible to catch fish on a bare hook if fished in a natural manner.

2. Get the weight of the Killer Bug right – it should sink quickly but not so quickly that the current doesn’t affect it.

3. The wool covering should be 2-3 layers only so that the copper wire beneath the wool gives the Killer Bug a translucent appearance when wet.

4. It doesn’t matter what colour the dry wool is, but when wet and wound over copper wire it should be grey/brown with a slight pink tinge.

5. Did I mention to get the technique right!

Killer Bugs made with the substitute wool and a booklet on the correct Killer Bug technique are available from my website [ed.-which is no longer in existence, but the flies are now sold through]

Tight Lines,

Nick Sawyer

The actual tying techniques are set forth best in Frank Sawyer’s books, rather than the infinite number of variations available on the Internet.

Killer Bug Nymph

Hook: straight-shank wet round bend hooks (barbed) down-eyed
Thread/weight: fine dark coloured (enamelled) copper wire
Tail/abdomen/thorax/wingcase: copper wire and a substitute Chadwick’s 477 wool