In response to "Earworms and white bears", D.R. writes:
There is an interesting, now archaic, usage of the term "maggot" to mean, as I was told anyway, the same as the modern word "earworm." The OED describes it thus:
c. Formerly used in the names of many dance tunes (now hist.). Now also arch. in the titles of other musical compositions.
1689 2nd Pt. Musicks Hand-maid sig. G3v, Motleys Maggot.
1695 Dancing-Master (ed. 9) i. 179 Betty's Magot.
1695 Dancing-Master (ed. 9) i. 180 Mr. Beveridge's Magot.
1695 Dancing-Master (ed. 9) i. 191 Huntington's Magot.
1695 Dancing-Master (ed. 9) i. 195 A Song made by Mr. Tho. D'Ursey upon a new country dance at Richmond, called, Mr. Lane's Magot.
1977 P. Maxwell Davies (title of musical composition) Miss Donnithorne's maggot.
1994 J. Buller (title of musical composition) Mr. Purcell's maggot.
When I used to do a lot of English country dancing, there were several such tunes we used, including "Mr. Beveridge's Maggot" and "Mr. Isaac's Maggot," both from Playford's English Dancing Master (first edition 1651, but the term "magot" appears in titles only from the 1695 edition, and is spelled "maggot" in later editions.
A couple of non-dancing examples from EEBO — one from 1682:
And another from 1687:
The OED says that maggot is "Probably an alteration of maddock n.", whose basic meaning is "earthworm", but which also is given the sense
2. Eng. regional (north.). A whim.