Robust flies, mostly dull gray, 2.5-18.0 mm long. Thorax usually vittate. Abdomen checkered, striped, banded, or spotted; markings usually shifting from brown to black or from dark to pale depending on light incidence; abdomen, especially terminalia, sometimes partly or entirely red.
Subscutellum concave (except in Nyctia Robineau-Desvoidy, which has a slightly swollen subscutellum). Abdominal sternites without sensilla trichodea (alpha setae). Female ovolarviparous and with short, largely non-telescopic terminalia; common oviduct with bilobed incubatory pouch. Bacilliform sclerites (processi longi; divded male stenite 10) shortened and widely diverging; phallus with undivided dorsomedian sclerotization. Posterior spiracles of larva I-III placed in a recession or cavity (except Amobia Robineau-Desvoidy, Macronychia Rondani and Oebalia Robineau-Desvoidy); peritreme of posterior spiracles of second and third instar larva incomplete and wihout a distinct ecdysial scar; all slits of posterior spiracles set at an acute angle relative to median plane. (Shewell 1987, Pape 1998)