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| 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). 1, Chrysotoxum cautum, male: head (1a) and abdomen (1b) from the side. 2, "Psarus abdominalis" (not British?), side view of head (2a), and antenna (2b). 3, Paragus haemorrhous, male: head from above (3a) and side (3b), and tip of wing (3c). 4, Psilota anthracina: head from side (4a), and wing (4b). 5a, Pipiza noctiluca: head from the side. 6a, Orthoneura elegans: antenna. 7a-b, Chrysogaster cemiteriorum: head from the side (7a), and wing tip (7b). 7c, "Chrysogaster nigricollis" (= ?), wing tip. 8, "Brachyopa conica" (not British?), with head in side view (8a). 9, Rhingia rostrata: male head from above (9a) and from the side (9b). 10, Ferdinandea cuprea, with (10a) details of labrum and lingua showing one maxilla and its palp. 11a, Cheilosia illustrata: male head from the side. 11b and 11c, Cheilosia leucorum: proboscis (11b) and wing tip (11c). 12, Scaeva pyrastri, female, and (12a) head of male. 13a, Doros profuges: 8-jointed female abdomen. 14, Sphaerophoria interrupta, male, with extremity of the abdomen (14a); 14b, Sphaerophoria interrupta, abdomen of female. 15a and 15b, Baccha elongata: abdomen and hind leg. 16, Sphegina clunipes. 17a and 17b, Neoascia podagrica: head from the side, and wing tip. [18, Physocephala rufipes (Conopidae), and details of head from the side (18a), proboscis (18b), and antenna (18c)]. From Walker (1851, Plate X), with approximate lengths (head to abdominal tip) indicated. • R. campestris, with assorted other Syrphidae (adult forms). Syrphidae. 1, Baccha elongata, female; 2, Neoascia podagrica, male; 3 and 4, Melanostoma scalare, male and female respectively; 5, Syritta pipiens, male; 6, Tropidia scita, male; 7 and 8, Sphaerophoria scripta, male and female respectively; 9, Sericomyia silentis, male; 10, Xylota segnis, male; 11, Rhingia camprestris, female; 12, Eupeodes luniger, male; 13, Episyrphus balteatus, female; 14, Helophilus transfugus L., female (= ?); 15, Chrysotoxum cautum, male; 16, Eristalis arbustorum, male. Adapted from C.O. Hammond (Colyer and Hammond, 1968).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, 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. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. Insects of Britain and Ireland: the genera of Syrphidae (hoverflies). Version: 27th July 2019. delta-intkey.com’.
