Published online by Cambridge University Press: 31 May 2012
The abdomen, as in other muscoid flies, is composed of a preabdomen of five pregenital segments, of which terga 1 and 2 are fused, thus giving the appearance of four segments. Sterna 1-7 or 1-8 form a relatively narrow chain of ventral segments (Fig. 11). The postabdomen, or genital segments, comprise segments 6-10, some of which are reduced, absent, or modified in other ways. The post-abdomen of the Sarcophagidae and Tachinidae usually is “fixed” (not retractable), whereas in the Muscidae and Calliphoridae it commonly is in the form of a retractable ovipositor, which is narrow and elongated when extended but in repose telescoped within the abdomen.