British Insects: the Families of Diptera


L. Watson and M. J. Dallwitz


Adult insects. Slender-bodied; stilt-legged. The face in lateral view not deeply excavated between the antennae and the edge of the mouth. Antennae 3 segmented (third segment short and rounded); ‘modified’; aristate; the arista dorsal. The second antennal segment not grooved. Ptilinal suture clearly defined. Mouthparts functional. The maxillary palps 1 segmented; porrect. Vibrissae absent. 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 subapical cell (almost closed), or without a sub-apical cell; with a closed anal cell. The anal cell short. The costa unbroken. Sub-costa apparent; reaching the costa independently of vein 1. Wing vein 6 present; reaching the wing margin. Wings with the lower calypter much reduced or absent. The hind femora thickened, with two rows of spines beneath. Tibiae without a dorsal pre-apical bristle. Hind tibiae without strong bristles in the basal 4/5. Abdomen constricted basally (Ichneumon-like in appearance).

Larvae and pupae. The larvae terrestrial; predatory (?); acephalic. The pupae enclosed within a puparium.

Comments. Abdomen long and thin, somewhat contracted basally. Thorax and abdomen blackish, legs yellowish brown. Wings long and narrow, the 1st basal cell over half the length of the wing. Ovipositor short and retractile.

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

British representation. 1 species in Britain. Genera 1; Megamerina dolium.

Illustrations. • Megamerina dolium (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.’.