British Insects: the Families of Diptera


L. Watson and M. J. Dallwitz



Adult insects. Very small to large (3–20 mm long). Antennae 3 segmented (the third segment annulated); ‘modified’; having the terminal segment annulated. Ocelli present; 3. Lower orbital bristles absent. Post-vertical orbital bristles absent. Mouthparts non-piercing (the proboscis short and fleshy). The maxillary palps 1 segmented, or 2 segmented; porrect. Vibrissae absent. Wings with a discal cell (small), or without a discal cell; without a sub-apical cell; with a closed anal cell. The anal cell relatively long, or short. The costa not extending around the entire wing. Sub-costa apparent; reaching the costa independently of vein 1, or joining vein 1 more or less where it joins the costa. The leading edge veins markedly stronger than the rest (often), or not noticeably stronger than the rest. Wing vein 6 present; reaching the wing margin. Wing vein 7 present; falling short of the wing margin. Tibiae without spurs. Feet with a triple pad beneath the tarsal claws.

Larvae and pupae. The larvae aquatic (breathing via an extensible tail segment), or terrestrial; saprophagous (on animal and plant remains), or mycophagous, or predatory (?); hemicephalic. The pupae without a puparium (but enclosed in the last, unmodified larval skin).

Comments. Sluggish, small to fairly large, flattened flies without bristles, usually with white, yellow or green markings, often metallic; including some wasp mimics. Resting with wings placed one above the other over the abdomen.

Classification. Suborder Brachycera; Division Tabanomorpha; Superfamily Stratiomyoidea.

British representation. 48 species in Britain. Genera 16; Beris, Chloromyia, Chorisops, Clitellaria, Eupachygaster, Microchrysa, Nemotellus, Neopachygaster, Oxycera, Odontomyia, Oplodontha, Pachygaster, Sargus, Stratiomys, Vanoyia, Zabrachia.

Illustrations. • Beris, Chrysomyia, Clitellaria, Chlorisops, Nemotelus, Pachygaster, Stratiomys (from Walker). • Microchrysa and Sargus: Walker. • Beris geniculata (Pale-kneed Beris: B. Ent. 337). • Beris geniculata (detail: B. Ent. 337). • Beris geniculata (dissections: B. Ent. 337). • Beris geniculata: B. Ent. 337, legend+text. • Beris geniculata: B. Ent. 337, text cont.. • Sargus bipunctatus (Reaumur's Fly: B. Ent. 305). • Sargus bipunctatus (detail: B. Ent. 305). • Sargus bipunctatus (dissections: B. Ent. 305). • Sargus bipunctatus: (B. Ent. 305, legend+text. • Sargus bipunctatus: (B. Ent. 305, text cont.. • Oxycera morrisii Curtis (Lyme Regis Oxycera: B. Ent. 441). • Oxycera morrisii (B. Ent. 441, legend+text). • Oxycera morrisii (B. Ent. 441, text cont.). • Pachygaster leachii Curtis (Leachian Pachygaster: B. Ent. 042). • Pachygaster leachii (B. Ent. 042, legend+text). • Pachygaster leachii (B. Ent. 042, text cont.). • Nemotelus nigrinus: B. Ent. 729. • Nemotelus nigrinus: B. Ent. 729, legend+text. • Nemotelus nigrinus: B. Ent. 729, text cont.. • Clitellaria ephippium, Chorisops tibialis: Stephens 1846.

To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. British insects: the families of Diptera. Version: 1st January 2012.’.