Pegomya incisiva Stein 1906

10. Pegomya incisiva Stein, 1906

(Figs 33, 42, 51, 60, 72, 73)

Pegomyia incisiva Stein, 1906: 73.

Pegomya incisiva Stein. Hennig 1973b: 588, text fig. 506, table figs 759, 903; Hackman 1976: 133; Hackman 1979: 63; Hackman & Meinander 1979: 74; Suwa 2013: 184, figs 181‒185.

Pegomya (Phoraea) incisiva Stein. Griffiths, 1983: 248, figs 346‒350.

For further references, see Hennig (1973b) and Griffiths (1983).

Description. Different from P. z o na t a as follows: Size. Slightly larger, wing length up to 6.2mm. Male. Antenna orange yellow on scape, pedicel and basal part of postpedicel. Palp yellow. Setation on postgena all black. Abdomen ochre yellow apart from narrow dark bands at hind margins of tergites I‒IV, covered in whitish grey dusting. Legs, including all femora, entirely yellow. Terminalia (Figs 33, 42, 51, 60): Sternite V with backward rather than downward pointing inner lamellae; shape of postgonite and distiphallus species diagnostic. Female. Postpedicel yellow on less than basal third, brownish black on remaining part. Palp yellow. Setation on postgena all black. Thorax yellow or ochre yellow, frequently darkened along a median scutal stripe that sometimes widens to include discal part of scutum between intra-alar setal rows. Legs, including tarsi, yellow. Oviscapt (Figs 72, 73): Sternite VIII pieces broader with scattered fine setulae and sensilla on at least apical half; hypoproct less desclerotized, broadest beyond middle; cerci slender, laterally convex, apically tapered and ending in regular fine cutting blades.

Material examined. [FMNH, MZLU, NHMO, ZMUB, ZMUC]. CZECH REPUBLIC: South Bohemia. DENMARK: Bornholm: Paradisbakkerne, 1♂ 25.vi.1964 (O. Martin & B.V. Pedersen). FINLAND: Regio aboensis, Nylandia, Karelia australis, Satakunta, Ostrobottnia australis, Savonia borealis, Karelia borealis, Ostrobottnia kajanensis, Ostrobottnia borealis, Lapponia kemensis, Lapponia inarensis, Lapponia enontekiensis. NORWAY: Østfold & Akershus, Hedmark, Oppland, Buskerud, Telemark, Sør-Trøndelag, Troms, F innm ark. RUSSIA: Karelia, Murmansk, Sakha: Vilui river nr. junction with Lena river, 1♀ 24.vii. 1901 (B. Poppius). SLOVAKIA: Prešov. SWEDEN: Skåne, Halland, Småland, Västergötland, Bohuslän, Uppland, Värmland, Dalarna, Jämtland, Västerbotten, Norrbotten, Åsele Lappmark, Lycksele Lappmark, Lule Lappmark, Torne Lappmark.

Distribution. PALEARCTIC. Northern and central Europe from Britain and Fennoscandia in the north to northern France and the Czech Republic in the south. Outside Europe recorded from Sakhalin (Suwa 2013) and presently from East Siberia: Sakha. NEARCTIC. Widely distributed in boreal and alpine parts of Canada and USA according to Griffiths (1983).

Biology. In southern Finland (Hackman 1976, Hackman & Meinander 1979) and Finnish Lapland (Ståhls et al. 1989) reared from larvae in bolete sporocarps of the Leccinum versipelle and L. scabrum species groups (Boletaceae). Griffiths (1983) reported a male specimen claimed to be bred from an unidentified gilled mushroom in Yukon Territory. The female has an oviscapt with acutely pointed cerci which, according to Hackman (1976), are used to insert her eggs within the stalk of the host bolete; the developing larvae feed primarily or entirely on stalk tissue.