British Insects: the Families of Diptera


L. Watson and M. J. Dallwitz



Adult insects. Very small (about 3 mm long); winged. Antennae 3 segmented; ‘modified’ (the second segment projecting like a hood over the third); aristate; the arista dorsal (plumose). The second antennal segment not grooved. Ptilinal suture clearly defined. Post-vertical orbital bristles present; divergent. Mouthparts functional. The maxillary palps 1 segmented; porrect. Vibrissae absent. Thorax without a continuous dorsal suture; without well defined posterior calli. Wings without a sub-apical cell; without a closed anal cell. The costa unbroken. Sub-costa apparent; terminating blind (visible only basally). Wing vein 6 present; falling short of the wing margin (feeble). Wings with the lower calypter much reduced or absent. The legs with brown and yellow bands. Tibiae without a dorsal pre-apical bristle. Hind tibiae without strong bristles in the basal 4/5. Neither parasitic nor predatory (feeding on exudates of trees).

Larvae and pupae. The larvae terrestrial; saprophagous (associated with tree wounds); acephalic. The pupae enclosed within a puparium.

Comments. Greyish flies, with brown-and-yellow banded legs. Tibia without dorsal preapical bristles, by contrast with Drosophilidae.

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

British representation. 3 species in Britain. Genera 1; Periscelis.

Illustrations. • Periscelis.

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.’.