Named after a cat (from which the fur was taken for the dressing) which belonged to Dr. Norman McCaskie, a member of the Flyfishers' Club, this pattern proved a great lure for both trout and grayling. The full story of the fly is recounted by Mr. Skues in his Sidelights, Side-Lines, and Reflections, and I cannot do better than give an extract from what he writes there.
"I have taken and lost a good many good fish by its agency ---but I have never been able to reproduce with my hackle the action and appearance of a wet and disconsolate daddy long legs in the throes of dissolution, so I have never been as successful as McCaskie with this particular pattern.
I have, however, found that when in the day time the trout are taking blue-winged olive nymphs (and they never, or almost never, take the blue-winged olive in sub-imago form during the day) a fly dressed on a No. 1 hook with pale orange silk dubbed lightly and loosely with McCaskie's Green Cat and hackled lightly with soft dark blue henny hackle and glycerined to sink properly is really effective, even in the hands of an angler who has a prejudice in favour of thinking he knows why he uses any particular pattern rather than another".
It will often be taken in the day-time when the b.-w.o. is hatching and again in the evening. Also a good grayling pattern.
The dressing is as follows:
Tying silk : Pale orange waxed with clear wax. (I used YLI 100 Apricot)
Hackle: Soft dark blue henny cockeral as blue as possible (like the blue wing of a b.-w.o.). I mixed dark and medium blue dun hen to try and get the right shade.
Whisks: Soft honey dun cock's shoulder hackle.
Body: Blue cat's fur, dyed for thirty-six hours in picric acid. (yes, it's the real thing)
Hook: No. 14 or 13 t.d.e. round bend.
Regards,
Mark
