Insects of Britain and Ireland: the genera of Syrphidae (hoverflies)
Adult flies. The flies bumblebee-like (cf. Bombus terrestris and B. lucorum); black with coloured hair bands; medium sized to large; 11–16 mm long. Wings (11–)12–13(–14) mm long.
The head less wide than the thorax. The face flat or concave in the region between the antennae and the mouth; without a central knob. The eyes bare. Antennae relatively short, drooping; with their bases well separated; yellowish. 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 shaggy with soft hair; patterned (brown-haired anteriorly and black-haired posteriorly, with a clear line of demarcation across the middle); without longitudinal stripes. The scutellum black. Wings patterned (with a dark patch extending halfway across the disc from the costa); with a conspicuous dark stigma to without a conspicuously dark stigma. 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 without 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 strongly stepped. The upper outer marginal cross-vein conspicuously bent near the base the base; not re-entrant. The alula distinct.
The abdomen much wider than the thorax; very broadly obovate. The male abdomen with 4 visible segments. The abdomen conspicuously furry; contrastingly patterned. The patterning attributable to the furry hair coat. The tergite patterning involving 3 and 4 (with banding and tailing effected by the abdominal hairs, viz., black anteriorly and white on the tail, with an interrupted orange-tawny band on tergite 3 between). The colour-patterned tergites marked with tawny to orange. The spiracles of the third abdominal segment borne at or near the anterior corner of each side.
Larvae and pupae. The larvae tapering posteriorly; shortly tailed. The anal segment tapered gradually to the spiracular process; shorter than the rest of the body. The larvae scarcely flattened (sub-cylindrical, the small prolegs with 7 or 8 primary crochets); dark brown, plain; without thoracic hooks; mouth without triangular sclerites; anal segments with lappets. The larvae saprophagous; in rot-holes (above ground level in trees, especially beech).
Classification. Subfamily Milesiinae; tribe Xylotini.
British representation. 1 species in Britain (P. personata). Recorded from southern England to north Yorkshire.
Illustrations. • P. personata (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’.