proboscis

Unlike the proboscides of Lower brachyceran lineages, which are continuous with the head capsule and tend to dangle (Matsuda 1965), the proboscides of most cyclorrhaphan species are suspended by a membranous region and divided into three functional parts: the basiproboscis (rostrum), medioproboscis (haustellum), and distiproboscis (labellum), each of which is defined by internal muscles but also shares muscles with the other regions (Graham-Smith 1930; Lall and Davies 1971).