British Insects: the Families of Diptera


L. Watson and M. J. Dallwitz


Cellar-flies, Small Fruit-flies, Vinegar-flies.

Adult insects. Very small to small; winged. Antennae 3 segmented (third segment short and rounded); ‘modified’; aristate (the arista usually plumose, and characteristically forked at the tip); the arista dorsal. The arista characteristically, conspicuously forked at the tip. The second antennal segment not grooved. The third segment not elongated (short and rounded). Ptilinal suture clearly defined. Ocelli present; 3. Lower orbital bristles present, or absent; when present, curved forward. Post-vertical orbital bristles present; convergent, or parallel. Mouthparts functional; non-piercing. The maxillary palps 1 segmented; porrect. Vibrissae present to absent (i.e., sometimes indistinct). Thorax without a continuous dorsal suture; without well defined posterior calli. Wing venation complete, in the sense of exhibiting 1st and 2nd basal, anal and discal cells, or incomplete, in the sense of lacking one or more of the cells. Wings with a discal cell (in a few genera), or without a discal cell (usually confluent with the basal cell); without a sub-apical cell; with a closed anal cell. The anal cell short. The costa with two breaks (near the humeral cross vein, and near the end of vein 1). Sub-costa apparent; terminating blind, or joining vein 1 well short of the costa. Wing vein 4 extending far beyond the end of the first basal cell. Wing vein 6 present; falling short of the wing margin. Wings with the lower calypter much reduced or absent. The legs with brown and yellow bands (rarely), or without brown and yellow bands. Tibiae with a dorsal pre-apical bristle. Hind tibiae without strong bristles in the basal 4/5. Neither parasitic nor predatory.

Larvae and pupae. The larvae terrestrial; saprophagous, or mycophagous, or predatory (most seemingly fungiferous, often on yeasts in decaying fruits); acephalic. The pupae enclosed within a puparium.

Comments. Very small to small flies, often with light red eyes, often attracted to fermenting substances - strongly associated with manufacture of beer, cider, vinegar, and pickles. With two or three pairs of orbital bristles, the front ones usually curved forwards.

Classification. Suborder Brachycera; Division Muscomorpha Schizophora Acalyptratae; Superfamily Ephydroidea.

British representation. 59 species in Britain. Genera 8; Acletoxenus, Amiota, Cacoxenus, Chymomyza, Drosophila, Leucophenga, Scaptomyza, Stegana.

Illustrations. • Drosophila cameraria (Hairy-thoraxed Cellar-fly: B. Ent. 473). • Drosophila cameraria (detail: B. Ent. 473). • Drosophila cameraria (dissections: B. Ent. 473). • Drosophila cameraria: B. Ent. 473, legend+text. • Drosophila cameraria: B. Ent. 473, text cont.. • Drosophila melanogaster: Walker.

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.’.