Insects of Britain and Ireland: the genera of Syrphidae (hoverflies)
Adult flies. The flies somewhat resembling a mining bee (cf. Andrena marginata), or halictid bee-like (cf. Sphecodes gibbus); black marked with tawny; small; 6–11 mm long. Wings 6–9.5 mm long.
The head wider than the thorax to about the same width as the thorax. The face without a central knob; produced below and extending beyond the antennae; drawn out into a horizontal cone as long as the rest of the head (characteristically very long-snouted). The eyes bare; rimmed along their facial borders for much of the height of the face (?). Antennae relatively short, drooping; with their bases approximated (seated on a tubercle); pale red, or tawny. The third antennal segment ovoid or orbicular. The antennal bristle dorsal; much longer than the third segment; simple (pubescent).
The humeri hairy, and readily visible behind the head. The thorax pubescent without stiff bristles interspersed; patterned to plain; with longitudinal stripes (sometimes, dusted with pale stripes), or without longitudinal stripes. The scutellum of R. rostrata dark tawny, clothed with yellow hairs. Wings plain (extending beyond the abdomen, pale grey with 5 vinereous stripes and tinged tawny basally and along the fore border to the stigma); without a conspicuously dark stigma (this tawny); divergent 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; 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 slightly stepped. The upper outer marginal cross-vein conspicuously bent near the base the base; not re-entrant. The alula distinct.
The abdomen wider than the thorax to about the same width as the thorax; oval, or obovate. The male abdomen with 4 visible segments. The abdomen contrastingly patterned, or not contrastingly patterned (in the sense that in R. rostrata the bands are so wide as to render all the tergites tawny). The colour-patterned tergites marked with tawny (when identifiable as such). The tergite bands medianly interrupted (in R. campestris); wide. The spiracles of the third abdominal segment borne at or near the anterior corner of each side.
Larvae and pupae. The larvae broader posteriorly, tapered to the head, or tapering anteriorly and posteriorly from the middle (the body invested with stiff pubescence, and abdominal segments 6–8 with long, black papillae); posteriorly blunt and tail-less; flattened (prolegs absent); plain; without thoracic hooks; mouth without triangular sclerites; anal segments with lappets (three conspicuous, stick-like pairs). The larvae coprophagous (found in cow pats).
General comments. Wing vein 2 (R4+5) meeting the costa far below the apex of the wing, and the face extended below into a long, porrect snout..
Classification. Subfamily Milesiinae; tribe Cheilosiini.
British representation. 2 species in Britain.
Illustrations. • Rhingia campestris (Chequered-bodied Hover-fly: B. Ent. 182). • Rhingia campestris: B. Ent. 182, legend+text. • Rhingia campestris: B. Ent. 182, text cont.. • R. campestris: Verrall. • 18 genera (from Walker). • R. campestris, with assorted other Syrphidae (adult forms).
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’.