Insects of Britain and Ireland: the genera of Syrphidae (hoverflies)
Adult flies. The flies megachilid bee-like (cf. Coelioxys spp.); black to blue-black, with with greyish abdominal markings; medium sized; 12–13 mm long. Wings 8–10 mm long.
The head wider than the thorax to about the same width as the thorax. The face ground-coloured at least part yellow. The eyes bare. Antennae relatively short, drooping; black. The third antennal segment ovoid or orbicular. The antennal bristle dorsal; about as long as the third segment to much longer than the third segment; simple.
The humeri hairy, and readily visible behind the head. The thorax patterned; with longitudinal stripes (with brownish stripes). Wings plain (greyish); without a conspicuously 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 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 slightly diverging from the posterior wing margin to 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 gently curved; 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; elongate- obovate. The male abdomen with 4 visible segments. The abdomen contrastingly patterned. The tergite patterning involving 2 to 4. The colour-patterned tergites marked with whitish, or silvery or greyish. The tergite patterning comprising pale, straight, obliquely longitudinal markings on either side. The spiracles of the third abdominal segment borne at or near the anterior corner of each side.
Larvae and pupae. The larvae tailed (?). The larvae saprophagous, or phytophagous and saprophagous (associated first with floating pond and ditch plants such as Lemna, then completing their development in decaying vegetation in organic mud on the bottom).
Classification. Subfamily Milesiinae; tribe Eristalini.
British representation. 1 species in Britain (L. vittatus). A scarce coastal species, seemingly confined in the British Isles to England.
Illustrations. • Lejops vittatus (Yarmouth Hover-fly: B. Ent. 429). • Lejops vittatus (detail: B. Ent. 429). • Lejops vittatus (dissections: B. Ent. 429). • Lejops vittatus: B. Ent. 429, legend+text. • Lejops vittatus: B. Ent. 429, text cont.. • L. vittatus: 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. delta-intkey.com’.