British Insects: the Families of Diptera


L. Watson and M. J. Dallwitz



Adult insects. Small to medium-sized; slender-bodied to robustly-built. The face in lateral view deeply excavated between the antennae and the edge of the mouth. Antennae 2 segmented, or 3 segmented; ‘modified’; aristate; the arista dorsal (not plumose). The second antennal segment not grooved. Ptilinal suture clearly defined. Eyes rounded, well separated. Post-vertical orbital bristles present; convergent (mostly), or parallel to divergent. Mouthparts functional. The maxillary palps 1 segmented; porrect. 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. Wings with a discal cell; with a closed anal cell. The anal cell short. The costa unbroken. Sub-costa apparent; reaching the costa independently of vein 1. The leading edge veins not noticeably stronger than the rest. Wings without a ‘vena spuria’. Wing vein 6 present; reaching the wing margin (but faint). Wings with the lower calypter much reduced or absent. Hind tibiae with strong bristles in the basal 4/5.

Larvae and pupae. The larvae aquatic; saprophagous (in decaying seaweed, regularly inundated by the tide); acephalic. The pupae enclosed within a puparium.

Comments. Small to medium sized, very bristly or hairy, rather flattened flies of the seashore.

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

British representation. 2 species in Britain. Genera 1; Coelopa.

Illustrations. • Fucomyia frigida (from 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.’.