Egle parvaeformis Schnabl, 1911

Michelsen, Verner, 2009, Revision of the willow catkin flies, genus Egle Robineau-Desvoidy (Diptera: Anthomyiidae), in Europe and neighbouring areas, Zootaxa 2043 (1), pp. 1-76 : 35-37

9. Egle parvaeformis Schnabl in Schnabl & Dziedzicki, 1911

Figs. 97–102 , 178, 179 .

Egle steini var. parvaeformis Schnabl in Schnabl & Dziedzicki, 1911: 105, plate figs. 251, 252, 781.? ‘ Hylemyia parva (Robineau-Desvoidy) ’; Ringdahl 1930: 5 (in part). Misidentification. Egle parvaeformis Schnabl ; Hennig 1967a: 144, plate figs. 139, 145, 151; Ackland 1970: 188, 191, figs. 1, 4, 6, 10, 11;

Draber-Moṅko 1991: 234; Dely-Draskovits 1993: 52; Chandler 1998: 166; Petersen 2001: 184; Griffiths 2003:

2324, figs. 2625–2630; Michelsen 2004. For further references, see Griffiths (2003).

Description. Small: wing length 3.2–3.9 mm.

Male. Parafacial in middle narrower than postpedicel. Lower facial margin projected well beyond level of fronto-parafacial angle. Genal setae in 2–3 irregular rows. Prealar seta variable, ranging from half as long to same length as posterior notopleural seta. Notopleuron with 0–3 accessory setulae around posterior notopleural seta. Proepisternals 2; proepimerals 3–4. Lower calypter forming a distinct lobe, fully half as long as upper calypter. Submedian tibial setae: fore tibia with 0–1 hair-like pd- and 0 p-setae; mid tibia with 0 ad-, 1 pd- and 0 p-setae; hind tibia with 2–4 short av- and 0–6 short p–pv-setae. Hind femur with short pv-setae on basal two-thirds. Tergite VI separate from syntergosternite VII+VIII. Sternite V ( Figs. 97, 98 ) diagnostic in respect to shape and vestiture of posterior lobes; setal tufts formed postero-laterally on basal plate consisting of 7–10 setae and setulae. Terminalia ( Figs. 99–102 ): shape of cerci and surstyli diagnostic.

Female. Prementum mat, covered in thin dusting. Parafacial in middle slightly narrower than postpedicel. Lower facial margin projected well beyond fronto-parafacial angle. Prealar seta ranging from three-quarters as long to same length as posterior notopleural seta. Notopleuron with 0–1 accessory setula around posterior notopleural seta. Proepisternals 2; proepimerals 2–3. Lower calypter forming a distinct lobe nearly half as long as upper calypter. Submedian tibial setae: fore tibia with 0–1 pd- and 0 p-setae; mid tibia with 1 ad-, 1–2 pd- and 0–1 p-setae; hind tibia with 1–2 short av-setae. Hind femur on basal half with 3–4 very short and fine pv-setae. Oviscapt ( Figs. 178, 179 ): Sternite VII largely membranized on posterior two-thirds. Sternite VIII a pair of small elongate plates with a pair of fine setulae and some sensilla at hind margin. Epiproct with pair of setulae; hypoproct somewhat membranized towards base, with several setulae along apical margin. Cerci moderately slender, free apices distinctly tapering. Spermathecae two normal-sized, finely cross-wrinkled, third spermatheca strongly reduced in size and with shortened duct.

Material examined. CZECH REPUBLIC [ ZMUC]: Bohemia mer.: Horusický rybník, 1 male 24.v.1970 (M. Chvála) . DENMARK [ ZMUC]: S Jutland: Birkepøl, Als , 2 males 23.iv.1984 ( V. Michelsen). W Jutland: Ulfborg Skovdistrikt, 1 female 5–8.vi.1980 (S. Andersen & V. Michelsen). NE Zealand: Søndersø, 1 male 7.v.1987 ( V. Michelsen) . FINLAND [ FMNH, ZMUC]: Karelia australis: Vehkalahti , 1 male 1.vi.1977 (L. Tiensuu). Ostrobottnia australis: Alavus, 9 males 14.v.1940 (L. Tiensuu). Lapponia enontekiensis: Kilpisjärvi, 1 male (W.E. Hellén) . NORWAY [ ZMUC]: Rogaland (outer): Stavanger: Krossberg , 1 male 24.iv.1982 (K. Rognes) . SWEDEN [ MZUL, ZMUC]: Skåne: Hälsingborg , 4 males 8.v.1929 (O. Ringdahl); Söderåsen, 1 male 10.v.1931 (O. Ringdahl); Skanör, 2 males 5.v.1955 (P. Ardö); Ängelholm, 1 female 25.iv.1948 (O. Ringdahl) . Halland: Mästocka ljunghed, on Salix repens , 1 female 4.v.2008 ( V. Michelsen). Småland: Kärshult, Sporda, on Salix repens , 1 male 2 females 2–3.v.2008 ( V. Michelsen). Torne Lappmark: Abisko, 1 male 10.vi.1975 (B.G. Svensson). Nearctic specimen seen from : CANADA [ ZMUC]: Manitoba: Churchill , 1 male 25.vi,1948 (G.E. Shewell) .

Biology. Adults of both sexes feed on male catkins of willow, e.g. on Grey willow ( Salix cinerea L.) and Creeping willow ( S. repens L.) in Denmark and southern Sweden. There are no breeding records, but the larvae certainly develop in the female catkins of willow.

Distribution. A Holarctic species. Nearctic distribution summarized by Griffiths (2003): mainly a boreal and cool temperate species but reaching northern California on the Pacific coast and Virginia on the Atlantic coast. In Europe reliably recorded from British Isles ( Ackland 1970), Czech Republic ( Michelsen 2004), Denmark ( Petersen 2001), Poland ( Hennig 1967b) and the Fennoscandian countries ( Michelsen 2004). Records from Austria ( Hennig 1967b) and Germany ( Hennig 1967b; Teschner 1999; Michelsen 2004) are based on unreliable determinations. Not yet confirmed from the East Palaearctic Subregion. According to my notes, one male recorded by Ringdahl (1930) as ‘ Hylemyia parva R.D.’ from Kamtchatka belongs to the present species, but it might as well belong to the very similar E. pseudosteini Griffiths , a widespread boreal to low arctic species described recently from Canada and Alaska.

Relationships. As judged from the structure of the male terminalia the present species is very close to the Nearctic E. pseudosteini Griffiths, 2003 , but that species has from 12–24 setae in the setal tufts on sternite V and apical extension of cerci with a distinct pair of short apical setulae.

Figures

FIGURES 97–102. Egle parvaeformis, male terminalia. 97, 98. Sternite V, ventral and lateral views. 99, 100. Hypopygium, caudal and lateral views. 101. Pre- and postgonites, lateral view. 102. Phallus, lateral view. Same scale.

FIGURES 176–179. Egle spp., female terminalia. 176. E. atomaria, oviscapt, flat mounted. 177. Same, spermathecae. 178. E. parvaeformis, oviscapt, flat mounted. 179. Same, spermathecae. Different scales.