Wikipedia
Yumboes are a kind of fairies in the mythology of the Wolof people (most likely Lebou) on Goree Island ( Senegal, West Africa). They are described as about two feet in height, and of a pearly-white colour; the latter is an often found property of supernatural beings in African beliefs. The Yomboes are said to have silver hair.
The Yumboes live beneath the Paps hills, and come out to dance in the moonlight. They feast on large tables, served by partially invisible servants (only feet and hands are visible). The Yumboes eat corn (which they steal from the humans) and fish (which they catch on their own). They do invite both natives and foreigners to their feasts.
The alternatively used name Bakhna Rakhna literally means good people, an interesting parallel to the Scottish fairies called Good Neighbours.