This one appears in Mike Weddell's 10 of the Best New Zealand Trout Flies. It certainly is one of the most often used dry flies fished in New Zealand and a must for your fly box. I particularly like the Coch-Y-Bondhu because it is an easy fly to tie quickly. Nothing complicated about this one.
Weddell prefers to tie his with a tail of ginger hackle fibres as it helps it to float better in faster broken water. The traditional tie has a small amount of gold tinsel wrapped around the curve of the hook. As someone who ties the Hopes Silvery with rabbit fur I certainly won't argue with adding a tail to a Cochy!
The Coch-Y-Bondhu fly is a beetle pattern of Welsh origin.
Hook size 6-14
Tail: Ginger hackle
Body: Green or bronze peacock herl
Hackle: Furnace red/brown
Tail: Gold tinsel wrapped around the hook.