Insects of Britain and Ireland: the genera of Syrphidae (hoverflies)
Adult flies. The flies hivebee-like (though some mainland-european species are sawfly- or bumblebee-like); black, with hairy abdomen; large; 15–17 mm long. Wings 11.25–12.5 mm long.
The head wider than the thorax to about the same width as the thorax. The face with a central knob. The eyes bare (in the British representative). Antennae relatively short, drooping. The third antennal segment ovoid or orbicular. The antennal bristle dorsal; much longer than the third segment; simple.
The humeri hairy, and readily visible behind the head. The thorax pubescent without stiff bristles interspersed (with dense tawny hairs); plain; without longitudinal stripes. The scutellum at least partly yellow, or brownish, ferrugineous or tawny. Wings somewhat patterned to plain (somewhat darkened towards the costa and in the mid-disc). Wing veins R2+3 and R4+5 not forming a closed cell (but almost doing so, the veins converging at the wing margin). The anterior cross vein R-M in cell R5 crossing it at or beyond the middle of the adjoining discal cell. Vein R4+5 with a conspicuous curve projecting into the cell R5; without a backwardly projecting, incomplete transverse veinlet. The lower outer marginal vein more or less parallel with the posterior wing margin. The upper and lower outer marginal cross veins more or less continuous. The upper outer marginal cross-vein gently curved (almost straight); not re-entrant. The alula distinct. The hind femur distally with neither a triangular plate nor a tooth.
The abdomen wider than the thorax to about the same width as the thorax; narrowly oval, or obovate. The male abdomen with 4 visible segments. The abdomen not conspicuously furry; not contrastingly patterned (black, with brownish hind margins to the tergites). The spiracles of the third abdominal segment borne at or near the anterior corner of each side.
Larvae and pupae. The larvae abruptly tapering posteriorly; tailed. The anal segment abruptly constricted basally into the long, narrow tail; at least as long as the rest of the body (rat-tailed). The larvae scarcely flattened; whitish, plain (the integument smooth and shiny, without projections or setae except for three short, fleshy, lateral projections on segment 7 just before the tail); without thoracic hooks; mouth without triangular sclerites; anal segments with lappets. The larvae semi-aquatic, or non-aquatic; probably saprophagous; in rot-holes (in deciduous trees).
General comments. The hind femur thickened.
Classification. Subfamily Milesiinae; tribe Eristalini.
British representation. 1 species in Britain (M. cimbiciformis). Throughout the U.K. to southern Scotland, seemingly absent from Ireland.
Illustrations. • M. cimbiciformis, male (with Caliprobola, Ferdinandea and Leucozona).
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’.