Insects of Britain and Ireland: the genera of Syrphidae (hoverflies)

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L. Watson and M. J. Dallwitz

Merodon Meigen

Lampetia, Syrphus p.p.

Adult flies. The flies bumblebee-like (cf. at least 5 British Bombus species), or resembling a potter bee; black, often furrily hair-banded gingerish and/or greyish to whitish on thorax and/or abdomen; small to medium sized; (10–)12–14 mm long. Wings 8.5–10.2 mm long.

The head less wide than the thorax. The face not flat or retreating between antennae and mouth; with a central knob; neither keeled nor impressed; short and smooth. The eyes hairy. Antennae relatively short, drooping. The third antennal segment ovoid or orbicular. The antennal bristle dorsal; simple (bare).

The humeri hairy, and readily visible behind the head. The thorax shaggy with soft hair; patterned, or plain (usually brown-haired anteriorly and black-haired posteriorly, with a clear line of demarcation across the middle, but brown-haired all over in a variety of M. equestris); without longitudinal stripes. The scutellum somewhat convex, with undefined edge. Wings 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 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 to slightly stepped. The upper outer marginal cross-vein gently curved; re-entrant. The alula distinct. The hind femur with a large triangular plate at its distal end.

The abdomen about the same width as the thorax to narrower than the thorax; almost cylindrical, obovate (or obconical, being almost straight sided). The male abdomen with 4 visible segments. The abdomen conspicuously furry to not conspicuously furry; contrastingly patterned, or not contrastingly patterned (banded black and brown, or black and pale greyish, or tailed brown or greyish, but only owing to hair tints). The patterning when manifest, attributable to the furry hair coat. 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 to tapering anteriorly and posteriorly from the middle; posteriorly blunt and tail-less; no more than flattened (prolegs absent); pale brown, plain; without thoracic hooks; mouth without triangular sclerites; anal segments with lappets (the middle pair each divided into two small projections). The larvae phytophagous; feeding on Alliaceae, Amaryllidaceae, Liliaceae, Zingiberaceae, and Hyacinthaceae (etc., i.e., divers monocot bulbs and rhizomes; seemingly responsible for causing rotting of commercial narcissus and onion bulbs).

General comments. The hind femur thickened, the legs all black.

Classification. Subfamily Milesiinae; tribe Merodontini.

British representation. 1 species in Britain (M. equestris). Throughout Britain and Ireland.

Illustrations. • Merodon clavipes (Beautiful Merodon Hover-fly. Extinct British species: B. Ent. 098). • Merodon clavipes: B. Ent. 098, legend+text. • Merodon clavipes: B. Ent. 098, text cont.. • M. equestris, male (with Cheilosia and Platycheirus. • 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.’.