B. pilosa is classified as rare with an apparent disjunct distribution being known only from a few sites in southern England and north-east Scotland (Shirt, 1987; Stubbs and Falk, 1983) (from Rotheray 1991).
Brachyopa (Brachyopa) pilosa Collin, 1939.
Collin, J.E. (1939) Notes on Syrphidae (Diptera). III. Entomologist's monthly Magagazine 75, 104-109.
Third instar larva (Rotheray 1991).
Overall appearance. A dorso-ventrally flattened larva having internal mouthparts, a coating of brown blotches, rows of transverse setae which are not regularly aligned, a tapering anal segment, a long prp and gradually elongating projections along the lateral margins.
Length. 7-9 mm; width: 2.5-3.5 mm; flattened dorso-ventrally (about twice as broad as high), slightly tapering anteriorly, tapering posteriorly; mandibles and mandibular lobes internal; lateral lips with base coated in spicules and tip coated in fine setae; dorsal and lateral margins of thorax and abdomen coated in pale brown blotches; abdominal segments 1-7 each with four transverse rows of setae, one row anterior and one row posterior to sensilla 1-3 and two rows in close proximity on the integumental fold posterior to that bearing sensilla 1-3; some of the setae comprising these rows are slightly anterior and posterior to each other so that they are not in straight lines; lateral margins with groups of setae surrounding sensilla 4-8; ventral surface coated with backwardly directed spicules, less so on the mesothorax and anal segment; anterior fold of the prothorax with a broad (>75% of anterior fold) spicule band .comprising >5 rows and reaching to sensilla 1; prolegs, as weakly produced transverse ridges, present on abdominal segments 1-6 and the mesothorax, with up to five crochets per proleg, crochets absent or reduced in number on abdominal segment 6; sensilla 1-7 on each abdominal segment on long basal papillae; each sensilla with up to five surrounding setae; anal segment about twice as long as sixth abdominal segment; dorsally anal segment consisting of two tapering folds, the first with two pairs of lappets and the second with a single pair; posterior respiratory process: length: 1.1 mm, width: at base 0.3 mm, at tip 0.24 mm; basal two-thirds matt with blotches, apical third dorsal surface shining and nodulate, ventrally shining without nodules; 3 pairs of spiracular slits.
unless otherwise stated