British Insects: the Families of Diptera
Inflated Flies, Spider-parasite flies.
Life style parasitic; on spiders.
Adult insects. Small; robustly-built (hunched-backed, grotesquely inflated). Antennae 2 segmented (ostensibly), or 3 segmented (in fact, the basal segment being concealed); modified; with a non-annulated terminal segment; aristate; the arista apical (Oncodes), or dorsal (Acrocera). Ocelli present; 3. Eyes asymmetric, nearly or quite connected above the antennae (holoptic in both sexes, occupying almost the entire head). Mouthparts non-functional (reduced or absent). The maxillary palps 1 segmented, or 2 segmented; porrect. Vibrissae absent. Wings without a discal cell; with a subapical cell, or without a sub-apical cell; with a closed anal cell. The anal cell relatively long. Sub-costa apparent; joining vein 1 more or less where it joins the costa. The leading edge veins markedly stronger than the rest. Wings without a sharp bend in vein 4. Wing vein 6 present. Wing vein 7 present; falling short of the wing margin. Wings with a well developed lower calypter. Feet with a triple pad beneath the tarsal claws.
Larvae and pupae. The larvae terrestrial; parasitic (on spiders); hemicephalic. The pupae without a puparium.
Comments. Small, bristle-less flies, with tiny spherical heads occupied mainly by the huge eyes, and very large squamae.
Classification. Suborder Brachycera; Division Asilomorpha; Superfamily Nemestrinoidea.
British representation. 3 species in Britain. Genera 2; Ogcodes, Paracrocera.
Illustrations. • Ogcodes gibbosus (Pale-margined Henops: B. Ent. 110). • Ogcodes gibbosus (detail: B. Ent. 110). • Ogcodes gibbosus (dissections: B. Ent. 110). • Ogcodes gibbosus: B. Ent. 110, legend+text. • Ogcodes gibbosus: B. Ent. 110, text cont.). • Ogcodes and Paracrocera (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. http://delta-intkey.com’.