Jim
I think the McDonald reference you're thinking of is from his article about trout fishing. First published in the May, 1946 issue of Fortune magazine and later republished in his book "Quill Gordon" in 1972.

His refernce is to "...the peerless school of Sullivan County (New York) flytiers..." He goes on to name some the tiers that we're all familiar with.

BTW, the color plates found in "Quill Gordon" are not exact dulicates of the Atherton illustrations produced for McDonald's Fortune magazine articles on trout and salmon fishing.