An Etymological Dictionary of the German Language/Mücke
Mücke, f., ‘gnat, midge,’ from MidHG. mücke, mucke, f., ‘gnat, fly’ (hence still ModHG. dial. ‘fly’), OHG. mucca, f. Goth. *mugjô is by chance not recorded; it is indicated by AS. myčǧe, f., E. midge, OSax. muggia, Du. mug. OIc. mý, n., ‘gnat,’ suggests the idea that the West Teut. guttural is a suffix, as in Brücke (see also Jugend). The common Teut. form of the noun is muwî, to which also Gr. μυῖα corresponds.