Insects of Britain and Ireland: the genera of Syrphidae (hoverflies)
Adult flies. The flies resembling a potter bee (cf. Anthephora furcata), or resembling a mining bee (e.g., Andrena chrysosceles); dark brownish to greenish, without conspicous marking; small to medium sized; 7–12 mm long. Wings 6–9.25 mm long (i.e, relatively short-winged).
The head about the same width as the thorax. The face entirely dark in ground colour; not flat or retreating between antennae and mouth; without a central knob. The eyes bare. Antennae relatively long, porrect (somewhat longer than the head); with their bases approximated (on a slight tubercle); black. The antennal bristle dorsal; shorter than the third segment; simple (setiform). The maxillary palps porrect.
The humeri hairy, and readily visible behind the head. The thorax shaggy with soft hair; plain; without longitudinal stripes. The scutellum ferrugineus. Wings relatively short, plain (pale grey); without a conspicuously dark stigma; incumbent and almost parallel in repose. Wing veins R2+3 and R4+5 not forming a closed cell. The anterior cross vein R-M in cell R5 crossing it before the middle of the adjoining discal cell. Vein R4+5 without a conspicuous curve projecting into the cell R5; with a short, backwardly projecting, incomplete transverse veinlet located distally to the cross veinlet in cell R5. The lower outer marginal vein markedly diverging from the posterior wing margin. The upper and lower outer marginal cross veins strongly stepped. The upper outer marginal cross-vein gently curved, or conspicuously bent well above the base; re-entrant. The alula distinct.
The abdomen much wider than the thorax; dumpy, oval, or obovate. The male abdomen with 5 visible segments. The abdomen conspicuously furry to not conspicuously furry; not contrastingly patterned (with only faint, ill-defined silvery reflections).
Larvae and pupae. The larvae not detectably segmented (slug-like in form, and originally described as molluscs!); posteriorly blunt and tail-less; short and hemispherical in shape, ventrally flattened (prolegs absent); patterned (with a reticulate pattern of dark setae), or plain. The larvae saprophagous and predatory (found in ants nests, seemingly scavenging and predacious at least on their pupae).
General comments. Relatively small-winged, the scutellum exhibiting two posterior teeth..
Classification. Subfamily Microdontinae.
British representation. 3 species in Britain.
Illustrations. • Microdon mutabilis (Bee-like Hover-fly: B. Ent. 070). • Microdon mutabilis: B. Ent. 070, legend+text. • Microdon mutabilis: B. Ent. 070, text cont.80. • M. analis, M. devius and M. mutabilis: Verrall. • 15 genera (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. Insects of Britain and Ireland: the genera of Syrphidae (hoverflies). Version: 28th July 2015. delta-intkey.com’.