\Mus"ca\, n.; pl. {Musc[ae]}. [L., a fly.]
1. (Zo["o]l.) A genus of dipterous insects, including the
   common house fly, and numerous allied species.
Note: Formerly, a large part of the Diptera were included
      under the genus {Musca}.
2. (Astron.) A small constellation situated between the
   Southern Cross and the Pole.
{Musc[ae] volitantes}. [L., flying flies.] (Med.) Specks or
   filaments apparently seen moving or glinding about in the
   field of vision. Their appearance is often a symptom of
   disease of the eye, or of disorder of the nervous system.