The fly box · No. 29 of 36
Green Rock Worm
Free-living green caddis larvae washed loose from the stones.
- Kind
- Nymph
- Hook sizes
- 12–16
- Season
- Spring, summer, autumn
- For
- Trout and grayling
- At the vice
- An easy tie
The dressing
| Hook | Curved heavy-wire grub hook, barbless, sizes 12–16 |
|---|---|
| Thread | Olive for the body, 8/0; black or dark brown for the head |
| Tail | None |
| Body | Bright green or insect-green dubbing, slim and slightly tapered, carried round the bend |
| Rib | Fine gold or copper wire, or clear monofilament, six turns |
| Hackle | None; a few dark fibres picked out under the head as legs |
| Wing | None |
| Also | Head of dark hare’s fur or one peacock herl, about a fifth of the body length; underbody of lead-free wire |
Tying it
- Wrap eight to ten turns of lead-free wire on the shank and bind them down.
- Take the thread round the bend and tie in the rib.
- Dub a slim green body forward, leaving room for the head.
- Wind the rib in even turns and tie off.
- Dub a short dark head, or wind a single peacock herl, and whip finish.
- Pick out a few fibres under the head to suggest legs.
Fishing it
Its place is the riffle and the fast water just below it, especially from late spring onward when the naturals are well grown. Fish it upstream on a short line with 5X (0.15 mm) tippet, close enough to the bed that it touches now and then, either on its own or as the heavier fly of a pair. A dead drift is all that is wanted, since the natural cannot swim. After a rise in water, when larvae have been dislodged, it can be the most useful nymph in the box.
Where it comes from
Green rock worm is the American angler’s name for the caseless caddis larvae that roam the stones of fast, clean riffles, and the fly is a traditional pattern with no single author. European rivers hold the same bright green larvae. When one loses its grip it drifts helplessly near the bottom, and trout and grayling lying in the riffle rarely let it pass.