British Insects: the Families of Diptera

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L. Watson and M. J. Dallwitz

Psilidae

Carrot Rust Fly, etc.

Adult insects. Small to medium-sized; slender-bodied to robustly-built; not 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 to long and thin); ‘modified’; aristate; the arista dorsal (not plumose). The second antennal segment not grooved. Ptilinal suture clearly defined. Post-vertical orbital bristles present, or absent; when present, divergent. Mouthparts functional. The maxillary palps 1 segmented; porrect. Vibrissae absent. Thorax without a continuous dorsal suture; without well defined posterior calli. Hypopleural bristles absent. 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 with one break (before the end of R1). Sub-costa apparent; terminating blind (i.e., vestigial distally, being represented there by a right-angled upward bend to the costal break manifested as a whitish or transparent streak). 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; falling short of the wing margin. Wings with the lower calypter much reduced or absent. Tibiae without a dorsal pre-apical bristle. Hind tibiae without strong bristles in the basal 4/5. Abdomen constricted basally (e.g., the black-and-red, Ichneumon-like Loxocera), or not constricted basally.

Larvae and pupae. The larvae terrestrial; phytophagous (including the Carrot-fly, which notoriously damages various root crops); acephalic. The pupae enclosed within a puparium.

Comments. Small to quite large flies of varied form. Wings with an apparent cross fold, running from the break in the costa across the end of the second basal and anal cells to the hind margin.

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

British representation. 26 species in Britain. Genera 5; Chamaepsila, Chyliza, Loxocera, Psila, Pilosoma.

Illustrations. • Chyliza extenuata (from Walker). • Psila fimetaria (from Walker). • Loxocera albiseta (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’.

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