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

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L. Watson and M. J. Dallwitz

Myolepta Newman

Leptomyia, Myiolepta; formerly Xylota p.p.

Adult flies. The flies black and orange; small to medium sized; 9–11 mm long. Wings 6–8.75 mm long.

The head about the same width as the thorax. The face not flat or retreating between antennae and mouth; with a central knob (male), or without a central knob (female); impressed. The eyes bare; not rimmed along their facial borders for much of the height of the face. Antennae relatively short, drooping; seated on a tubercle; ferruginous. 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; plain; without longitudinal stripes. The scutellum flat, with a well defined edge; black. Wings plain (colourless to slightly grey, with a brown spot in the middle of the fore border); with a conspicuous dark stigma; 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. Vein R without bristles. The lower outer marginal vein markedly diverging from the posterior wing margin to slightly diverging from the posterior wing margin. The upper and lower outer marginal cross veins slightly stepped. The upper outer marginal cross-vein basally gently curved; not re-entrant. The alula distinct.

The abdomen about the same width as the thorax to narrower than the thorax; ovate, or oblong. The male abdomen with 4 visible segments. The abdomen contrastingly patterned. The tergite patterning involving 1 and 2, or 1 to 3, or 2 to 3. The colour-patterned tergites marked with yellow, or tawny. The tergite bands medianly interrupted (the black median markings forming distinctive, inkwell-shaped patterns: see illustrations); wide (occupying the width of the segments, producing the unusual effect of a contrastingly black tail). The spiracles of the third abdominal segment borne at or near the anterior corner of each side.

Larvae and pupae. The larvae rather abruptly tapering posteriorly; tailed. The anal segment abruptly constricted basally into the long, narrow tail (not rat-tailed); shorter than the rest of the body (about half as long as the rest of the body, covered with papillae most of which bear tufts of setae). The larvae reaching 15–17 mm long, scarcely flattened; dirty whitish or pale brownish, plain; without thoracic hooks; mouth without triangular sclerites; anal segments with lappets. The larvae semi-aquatic to non-aquatic; saprophagous; in rot-holes (in deciduous trees).

General comments. The adults with a concave face leading smoothly to the projecting margin of the mouth.

Classification. Subfamily Milesiinae; tribe Chrysogastrini.

British representation. 2 species in Britain.

Illustrations. • M. dubia (Verrall).

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.’.