Strongylophthalmyia ustulata
Identification: Middle and hind femora brownish, with narrow apical band. Phallus apically dilated. Margin of penultimate abdominal tergite with narrow processes
Key in Palaczyk, A., Klasa, A., & Slowinska-Krysiak, I. (2013).
Distribution
Europe: Countries (published), online at Fauna Europaea, Occurrences at GBIF
UK: Recording Scheme map of occurrences 2016 (verified.) Online (NBN Atlas) via Easy maps or Interactive Atlas
Krivosheina, 1982: Male. Frons pale yellow before ocellar tubercle, including area level with median ocellus. Antennae, face, and parafacials also pale, yellowish. Arista with dark erect pubescence. Palps narrow, simple, brownish, with pale, slightly brownish hairs on undersurface and isolated stout black bristles on apex, Thorax and abdomen unicolorous, dark brown. Dorsal surface of scutum with, in addition to silvery pollen, pale, yellowish long and slightly appressed hairs forming practically continuous cover, especially before suture. Legs pale yellow. [Femora] slightly brownish. Hind femora apically with narrow dark brown band. Halteres pale. Wings transparent, with small pale apical darkening at end of R4+5.
Rotheray, 1998: Puparium. Length 4.25mm; width 1.25mm; tapering anteriorly, truncate posteriorly, dark red- brown in colour and, in both specimens studied, somewhat dorsoventrally flattened (Fig. 1); anterior spiracles (Fig. 2) bifurcating from a pale basal projection, each arm bearing 7-8 spiracular facets; posterior spiracles (Fig. 3) borne on short fleshy projections; spiracular plates inclined and irregular in outline bearing two outer spiracular openings and one inner; ecdysial scar dorsal in position; anal segment with a large fold laterally and ventrally; anus apparently lacking surrounding setae or spicules, locomotory organs (Fig. 5) comprising interrupted rows of spicules, some rows more interrupted than others; head skeleton (Fig. 4) with mandible, intermediate sclerite and parasomal bar black and heavily sclerotised, more so than pharyngeal sclerite which is translucent; mandible with narrow, curved mouth-hook and rectangular-shaped mandibular sclerite; crescent-shaped dental sclerite present; intermediate sclerite broader at tip; parasomal bar narrow; pharyngeal sclerite with dorsal apodeme and ventral pharyngeal ridges.
Distinguishing features. The bifurcating anterior spiracles, irregular-shaped posterior spiracular plate which is borne on a short fleshy projection and lacks an apical hook and the anus not surrounded by spicules, appear to distinguish this species from other acalypterate larvae and puparia.
Material examined. Two puparia collected in thick, wet, decaying cambial layers under the bark of a small (about 18cm diameter) dead standing aspen {Populus tremula) snag (tree with the top broken off) on 10.vi.1998 at Dulsie Bridge, Inverness-shire, adult females emerged a few weeks later. Additional Malloch Society records include a female reared by GE. Hancock on 21.vii.I990 at Dulicht Wood near Grantown, Inverness-shire from under bark of a fallen P. tremula and a male at the same site on 22.vii.1990, observed by R.M. Lyszkowski, emerging from the bark of a fallen P. tremula. Independently of the Malloch Society, adults were found by • 1. Perry {pers. comm.) at Dulsie Bridge in 1991.
Previous knowledge. Early stages of Strongylophthalmyia have apparently not been described previously, although Krivosheina (1984) gave a few details Strongylophthalmyia ustulata has been reared from under bark of P, tremula (Morge 1963; Krivosheina 1981) and adults have been found on fallen P. tremula in Finland (Frey 1935).