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| Insects of Britain and Ireland: the families of Diptera |
Marsh-flies.
Life style parasitic (in the larval stages); on slugs and snails.
Adult insects. Small to medium-sized. Not shining black. The face in lateral view not deeply excavated between the antennae and the edge of the mouth. Antennae 3 segmented (second segment sometimes thickened or elongated); ‘modified’; aristate; the arista dorsal (bare to plumose). The second antennal segment not grooved. Ptilinal suture clearly defined. Post-vertical orbital bristles present; parallel, or divergent. 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; 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. The leading edge veins not noticeably stronger than the rest. Wing vein 4 extending far beyond the end of the first basal cell. Wing vein 6 present; reaching the wing margin. Wings with the lower calypter much reduced or absent; patterned (sometimes with dark markings), or unpatterned. Tibiae with a dorsal pre-apical bristle. Hind tibiae without strong bristles in the basal 4/5.
Larvae and pupae. The larvae aquatic, or terrestrial; predatory, or parasitic (on slugs and snails, the terrestrial species parasitic and the aquatic species predatory); acephalic. The pupae enclosed within a puparium.
Comments. Head viewed dorsally as wide as, or wider than, the thorax. Small to medium sized flies of wet places, associated with snails.
Classification. Suborder Brachycera; Division Muscomorpha Schizophora Acalyptratae; Superfamily Scyomyzoidea.
British representation. 67 species in Britain. Genera 23; Anticheta, Colobaea, Coremacera, Dichetophora, Dictya, Ditaeniella, Ectinocera, Elgiva, Euthycera, Hydromya, Ilione, Limnia, Pherbellia, Pherbina, Psacadina, Pteromicra, Renocera, Salicella, Sciomyza, Sepedon, Tetaneura, Tetanocera, Trypetoptera.
Illustrations. • Salticella fasciata: B. Ent.621. • Salticella fasciata: B. Ent.621, legend+text. • Salticella fasciata: B. Ent.621, text cont.. • Pherbellia albocostata and Tetranocera ferruginea (from Walker). 2, Tetanocera ferruginea, with head in side view (2a), and antenna (2b). 7, Pherbellia albocostata, with side view of head (7a), and antenna (7b). From Walker (1853, Plates XIII and XIV), with 2mm scale added. • Sepedon sphegea (from Walker). Sepedon sphegeus: 4a, side view of head; 4b, hind leg. From Walker (1853, Plate XIV).
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’.
