The Dette’s tied this fly, the Conover, for the Brooklyn Fly Fishing Club member Scotty Conover back in the 1930's. The story goes that Dette’s weren’t allowed to tie for anyone else than him.
Mike Valla adds:
"I know in June 1972 I was fishing Conovers on Beaverkill---during that wonderful season I stayed with Dettes for over a month (that was my high school graduation present from them---check my "Tying Catskill Style Dry Flies" book for that Conover story (page 18). That's one of my favorite stories.
I caught that big brown trout at the tail of Barnhart's Pool, on BkilL, on a Conover. Landed it down at Hendricksons, with a crowd watching and applauding. All but Ernie Maltz---who yelled at me for not having a landing net. Then he yelled at me for fishing a 7ft Leonard (given to me by a Leonard dealer, also as a graduation present) who I figured had one too many glasses of Scotch)--rod much too short for that river. Anyway, I'm sure I tied the Conover myself. They way Walt explained it to Leiser ('The Dettes - A Catskill Legend', page 56) was once Scotty couldn't wade the river well any longer, he relaxed things--Dettes were allowed to sell them."