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| Insects of Britain and Ireland: the families of Diptera |
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). Megamerina dolium, with head viewed from the side (4a), and antenna (4b). From Walker (1853, Plate XVI), with 2mm scale added.
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, 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. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. Insects of Britain and Ireland: the families of Diptera. Version: 14th April 2022. delta-intkey.com’.
