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| Insects of Britain and Ireland: the families of Diptera |
Including Helcomyzidae
Sea-shore Flies.
Life style non-parasitic.
Adult insects. The face in lateral view deeply excavated between the antennae and the edge of the mouth, or not deeply excavated between the antennae and the edge of the mouth (Helcomyzidae). Antennae 2 segmented, or 3 segmented; ‘modified’; aristate; the arista dorsal (not plumose, very short in Helcomyza). The second antennal segment not grooved. Ptilinal suture clearly defined. Ocelli present; 3. Post-vertical orbital bristles present; parallel, or divergent. Mouthparts functional. The maxillary palps 1 segmented; porrect. Vibrissae present, or 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 (large by comparison with related genera, but extending less than a third of the way to the wing margin, though). The costa unbroken. Sub-costa apparent; reaching the costa independently of vein 1. Wings without a ‘vena spuria’. Wing vein 6 present; reaching the wing margin. Wings with the lower calypter much reduced or absent; patterned, 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 (e.g. Helcomyza ustulata, which live in dislodged seaweed and are inundated by each tide), or terrestrial; saprophagous, or coprophagous, or mycophagous; acephalic. The pupae enclosed within a puparium.
Comments. Yellowish or reddish brown flies of moist places, associated with rotting seaweed, putrifying matter or rotting fungi. Wings very large, much longer than the abdomen.
Classification. Suborder Brachycera; Division Muscomorpha Schizophora Acalyptratae; Superfamily Scyomyzoidea.
British representation. 6 species in Britain. Genera 5; Dryomyza, Neuroctena, Helcomyza, Heterocheila, Malacomyia.
Illustrations. • Dryomyza and Helcomyza (from Walker). 1a and 1b, Dryomyza flaveola: head in side view, and an antenna. 6, Helcomyza ustulata, with head in side view (6a), and an antenna (6b). From Walker (Plates XIII and XIV), with approximate length of insect added. • Helcomyza ustulata (Original genus and species descriptions. Sea-shore Helcomyza: B. Ent. 066). • Helcomyza ustulata (detail: B. Ent. 066). • Helcomyza ustulata (dissections: B. Ent. 066). • Helcomyza ustulata (B. Ent. 066, legend+text). The original descriptions of Helcomyza Curtis, and of H. ustulata Curtis. Although the names are credited to him in modern Check Lists, Curtis himself attributed both to Meigen. • Helcomyza ustulata (B. Ent. 066, text cont.).
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’.
