A modern approach to creating super-stimuli
In the late 19th century dubbed fur bodies fell out of favour because of a lack of reliable floatants: "Possibly at some future date a means of thoroughly waterproofing dubbing may be invented, and if so, I venture to predict that the dubbing body will entirely supercede the quill, as being so much more transparent and watery in appearance ..." (Halford 1886 p 14)
Fifty years ago, Lawrie (1967) outlined a rationale for using dubbed fur bodies in dry flies based on the difficulty in obtaining cock hackles of suitable stiffness to fully support a dry fly in the manner prescribed by Halford, or create the "light patterns" produced by a dun's feet on the water surface identified by Harding. Lawrie's book All-Fur Flies and How to Dress Them championed the use of all-fur dry flies.
There is little mention of Lawrie (1967) in today's fly-tying literature but, as Halford (1886) predicted, dubbed bodies are now commonplace. Natural furs have been joined by, and sometimes mixed with, artificial materials that are pretreated to remain buoyant, or trap air bubbles for a lifelike look.
But, even today, there are very few all-fur flies as championed by Lawrie. Two that spring to mind are Fran Betters' fly he named 'The Usual', and Bob Wyatt's Snowshoe Hare Emerger. Both flies are tied with the fur from a snowshoe rabbit's foot pad which is naturally waterproof, and traps air for insulation. When water is added this may coat the fur with bubbles that mimic, perhaps to a greater extent, the trapped air carried by aquatic insects. Ed Engle writes enthusiastically about this high-floating material that he puts down to the hairs' ability to trap air. He calls snowshoe-hare hair the "Poor Man's CDC". This poor man needed little convincing, and it seems I'm not alone: "waterlogged or slimed up CDC patterns are known to sink like a stone!" (Hans Weilenmann 2011)
These two flies are joined by Kenneth Boström's fly, the Rackelhanen (constructed from polypropylene yarn); all are graduates from the "Ugly Ducking School of Fly Dressing" which may account for their scarce commercial availability here in the UK.
Nevertheless, these are important flies in the search for what makes a super-stimulus trout fly because:
Each fly uses just one material to make both body and wing.
Together they cover surface, and sub-surface, presentation: dry fly (Usual), emerger (Snowshoe Hare Emerger), dry fly and nymph (Rackelhanen).
They are constructed from hydrophobic (hydrofuge) material that traps air in bubbles.