Thought I might as well add this from Wimberley's Folklore in the English and Scottish Ballads (p.307):

The Fause Knight upon the Road (3), an old ballad with a striking parallel in a curious Swedish piece, furnishes still another example of riddlecraft. Matched by a witchlike old crone in the Swedish song, the false knight here, none other than the devil himself, tries to nonplus a wee boy by asking him questions and making evil wishes. Needless to say, the youthful replicant is capable of clever rejoinders and has the last word, a matter of paramount importance in these verbal conflicts with Otherworld folk. Child observes that our ballad is known only through Motherwell, but it is interesting that copies have been recovered in America by Phillips Barry, H. M. Belden, and Cecil Sharp. The false knight is called the "fol fol Fly" in Barry's Maine text, a probable corruption, as Barry points out, of "foul, foul Fiend." This text, Barry further observes, retains "a form of the theme more primitive than that of Motherwell's version."

The only Barry publications I have are the Journals of the Folksong Society of the Northeast, edited by Bayard, and British Ballads from Maine, and I find no "fol fol Fly" text in either. Bruce, can you locate the Barry text Wimberley is referring to?

The Alan Kelly version appears in Bronson's addenda at the end of Volume 4, by the way, as it was originally recorded by Lee Haggerty for Folk-legacy: "Fol, Fol, Folly" and all.

Sandy