See quotations.

1

1612.  A fruite like vnto a muske millen,… which they call Macocks.—Capt. Smith, ‘Map of Virginia,’ p. 17. (N.E.D.)

2

1705.  Vetches, Squashes, May Cocks, Maracocks, Melons, &c.—Beverley, ‘Virginia,’ ii. 17

3