Thorax Dun Patterns

Thorax Duns are actually just a modification of the traditional Catskill style dry fly in that the wing and hackle are set a bit further back on the hook shank. In his book; A Modern Dry Fly Code published in 1950 Vincent Marinaro detailed this adaptation for fishing the flat limestone creeks of Pennsylvania.

Made for quiet water and finicky trout the hackle of a thorax dun is wound fore and aft of the upright wing then clipped on the bottom. This results in a fly that rides lower in the surface film thus creating a more natural looking mayfly silhouette. Thorax patterns are an excellent choice for a mayfly dun to use on selective feeding trout.

The thorax style of tying a pattern can be used with almost any mayfly dun pattern. It works well down to a hook size 22 and is especially effective for imitating male Trico duns and small Blue Winged Olives. It is advisable to use good quality hackle for tying thorax style patterns especially if you are wrapping the hackles at opposing a 45 degree angles to spread them out as Marinaro originally specified.


Adams Thorax Dun Pattern Recipe:
Hook- TMC 100 size 12-20, Thread- Gray 6/0, Wing- Natural dun deer hair, Tail- Grizzly hackle barbs split, Body- Natural Muskrat fur dubbing, Hackle- Grizzly and brown mixed and clipped on the bottom side. 

Blue Winged Olive Thorax Dun Pattern Recipe: Hook- TMC 100 size 12-20, Thread- Olive 6/0, Wing- Dyed gray turkey flat, Tail- Blue dun hackle barbs split,.
Body- Olive Antron dubbing, Hackle- Blue dun clipped on the bottom side.

Baetis Thorax Pattern Recipe: Hook- TMC100 sizes 18-22, Thread- Dark olive 6/0, Wing- Light dun turkey flat, Tail- Dun-gray hackle barbs, Body- Gray-olive Superfine dubbing, Hackle Light dun wound collar style clipped at bottom. Pattern Designer: Mike Lawson

Callibaetis Thorax Dun Pattern Recipe: Hook- TMC 100 size 12-18, Thread- Cream 6/0, Wing- Gray Partridge feather clump, Tail- Grizzly hackle barbs split,.
Body- Creamy Gray Antron dubbing, Hackle- Grizzly clipped on the bottom side.

Callibaetis Thorax Pattern Recipe Variation: Hook- TMC100 sizes 16-20, Thread- Cream 6/0, Wing- Light gray partridge feather clump, Tail- Grizzly hackle barbs, Body- Cream-gray Antron dubbing, Hackle- Grizzly wound collar style clipped at bottom. Pattern Designer: Mike Lawson

Dark Olive Thorax Dun Pattern Recipe: Hook- TMC 100 size 12-22, Thread- Olive Yellow 6/0, Wing- Gray turkey flat, Tail- Blue dun hackle barbs split,
Body- Dark olive Antron dubbing, Hackle- Blue dun clipped on the bottom side.

Hendrickson Thorax Dun Pattern Recipe: Hook- TMC 100 size 12-16, Thread- Olive 6/0, Wing- Gray turkey flat, Tail- Blue dun hackle barbs split, Body- Grayish tan natural fox fur dubbing, Hackle- Blue dun clipped on the bottom side.

Light Olive Thorax Dun Pattern Recipe: Hook- TMC 100 size 12-22, Thread- Light Green 6/0, Wing- Light gray turkey flat, Tail- Light blue dun hackle barbs split,.
Body- Light Green Antron dubbing, Hackle- Light blue dun clipped on the bottom side.

March Brown Thorax Dun Pattern Recipe: Hook- TMC 100 size 12-18, Thread- Tan 6/0, Wing- Tan turkey flat, Tail- Brown hackle barbs split, Body- Tannish brown natural fur dubbing, Hackle- Brown or furnace clipped on the bottom side.

Mahogany Thorax Dun Pattern Recipe: Hook- TMC 100 size 12-16, Thread- Brown 6/0, Wing- Dark gray turkey flat, Tail- Blue dun hackle barbs split, Body- Brown Antron dubbing, Hackle- Blue dun clipped on the bottom side.

Mahogany Thorax Dun Pattern Recipe Variation: Hook- TMC 5210 size 14-22, Thread- Brown 6/0, Wing- Dark gray turkey flat, Tail- Dark dun hackle barbs split, Body- Dark tan Antron dubbing, Hackle- Dark dun clipped on the bottom side. Pattern Designer: Mike Lawson

Pale Morning Dun Thorax Pattern Recipe: Hook- TMC 100 size 12-20, Thread- Pale Yellow 6/0, Wing- Light gray turkey flat, Tail- Blue dun hackle barbs split,.
Body- Pale yellow Antron dubbing, Hackle- Light blue dun clipped on the bottom side.

Pale Morning Dun Thorax Pattern Recipe Variation: Hook- TMC100 sizes 16-20, Thread- Pale olive 6/0, Wing- Medium gray turkey flat, Tail- Light dun hackle barbs, Body- Pale yellow-olive Antron dubbing, Hackle Light dun wound collar style clipped at bottom. Pattern Designer: Mike Lawson

Slate Olive Thorax Pattern Recipe: Hook- TMC100 sizes 14-22, Thread- Olive 6/0, Wing- Dark gray turkey flat, Tail- Dark dun hackle barbs, Body- Dark olive Antron dubbing, Hackle- Dark dun wound collar style clipped at bottom. Pattern Designer: Mike Lawson

White-Black Thorax Pattern Recipe: Hook- TMC5210 size18, Thread- Black 6/0, Wing- White turkey flat, Tail- Light dun hackle barbs, Body- Black Antron dubbing, Hackle- Light dun wound collar style clipped at bottom. Pattern Designer: Mike Lawson

Trico Dun Thorax Pattern Recipe: Hook- TMC 100 size 18-26, Thread- Black 8/0 Nylon, Wing- White turkey flat, Tail- Grizzly hackle barbs split, Body- Black Antron dubbing, Hackle- Grizzly clipped on the bottom side.