Face fly (Diptera: Muscidae) gynandromorph.

Single specimens of adult face fly, Musca autumnalis De Geer, gynandromorphs from laboratory and field populations are described and illustrated. The head of all individuals possessed male characteristics (i.e., a narrow interocular area when compared with the interocular area of females), and dorsal and ventral aspects of the abdomen possessed color patterns of both sexes. A possible mechanism of face fly gynandromorphism is discussed.