Musculature of the male genitalia of Chyliza vittata Meigen (Diptera, Psilidae)

Abstract

The skeleton and muscles of the male genitalia of Chyliza vittata Meigen, 1826 (Diptera, Psilidae) are described. Secondary symmetry of the male genital sclerites and development of secondary pregenital muscles in Chyliza may have resulted from reduction of segments VII and VIII. The absence of the ejaculator compressors M23 is recorded for the first time in Cyclorrhapha. Reduction has also partly affected the muscles of the epandrial complex. It is shown that the sclerites extending from the surstyles to the hypandrium in Chyliza vittata correspond to the subepandrial sclerite. In whole, the morphology of the male genital muscles in Chyliza is close to the ground plan of Cyclorrhapha, most probably due to reduction processes.