A very old grayling dry fly that has always struck me as a great looking fly.

Tiny_0002.jpg
Hook: Barbless dry fly 16 - 20 (I've used size 18 here).
Thread: Vevus 12/0 white.
Tail: Red Wool.
Body: Blue / Yellow Macaw Tail.
Hackle: Honey Dun Cock.

The blue and yellow of the body makes a kind of olive, and changes as the fly moves. It might make a great body for a Sparkle Dun. Hmm now there's an idea.
Cheers,
A.