British Insects: the Families of Diptera


L. Watson and M. J. Dallwitz



Adult insects. Very small to small; slender-bodied to robustly-built; stilt-legged, or not stilt-legged. Antennae 3 segmented (third segment variable in shape and adornment); ‘modified’; with a non-annulated terminal segment; aristate (usually), or not aristate (sometimes?); the arista apical, or dorsal (usually long and fine). Ptilinal suture absent or weakly defined. Ocelli present; 3. Mouthparts non-piercing (proboscis short, stout and retractable, the prey being crushed and milled between the labella). Mandibles present. Mandibles not in the form of long, slender, piercing stylets. The maxillary palps 1 segmented, or 2 segmented (flat, often much developed); porrect. Vibrissae absent. Wings without a discal cell (at least, with no cross-vein separating it from the 2nd basal cell); without a sub-apical cell (although veins 3 and 4 are sometimes depicted as converging somewhat); with a closed anal cell. The anal cell short. Sub-costa apparent, or absent or only dubiously identifiable; if identifiable, joining vein 1 well short of the costa. The leading edge veins not noticeably stronger than the rest. Wing vein 3 distally forked. Wing vein 6 present, or absent; when present, falling short of the wing margin. Wing vein 7 absent. Wings with the lower calypter much reduced or absent; patterned (with white or dark markings), or unpatterned. Feet with a triple pad beneath the tarsal claws, or without a triple pad. Predatory (on other arthropods and worms).

Larvae and pupae. The larvae aquatic, or terrestrial; saprophagous, or predatory (found in mud, rotting vegetation, etc.); hemicephalic. The pupae without a puparium.

Comments. Small, bristly, often metallic, bluish, greenish or bronze flies.

Classification. Suborder Brachycera; Division Asilomorpha; Superfamily Empidoidea.

British representation. 285 species in Britain. Genera 42; with very numerous species of Dolichopus, Cyrturella, and Rhaphium.

Illustrations. • Campsicnemus, Dolichopus, Hydrophorus, Orthoceratium, Orthochile, Raphium, Sciapus, Tachytrechus, Thinophilus (from Walker). • Anepsiomyia, Aphrosylus, Argyra, Chrysotus, Diaphorus, Dolichopus, Liancalus, Machaerium, Medeterus, Porphyrops, Raphium, Syntormon, Tachytrechus (from Walker). • Scellus notatus (Spotted-winged Medeterus: B. Ent. 162). • Scellus notatus (dissections: B. Ent. 162). • Scellus notatus (B. Ent. 162, legend+text). • Scellus notatus (B. Ent. 162, text cont.). • Raphium elegantulum (Bute Porphyrops: B. Ent. 541). • Raphium elegantulum (detail: B. Ent. 541). • Raphium elegantulum (dissections: B. Ent. 541). • Raphium elegantulum: B. Ent. 541, legend+text. • Raphium elegantulum: B. Ent. 541, legend+text. • Rhaphium monotrichum (Long-horned Rhaphium: B. Ent. 568). • Rhaphium monotrichum: B. Ent. 568, legend+text. • Rhaphium monotrichum: B. Ent. 568, text cont.. • Sciapus platypterus: as Psilopus platypterus, 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.’.