Egle subarctica ( Huckett, 1965 )

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 : 47-49

16. Egle subarctica ( Huckett, 1965)

Figs. 132–137 , 191, 192 .

Hylemya (Egle) subarctica Huckett, 1965: 99 , figs. 61, 150, 232, 232a.

Egle subarctica (Huckett) ; Ackland 1989: 219, figs. 22–24; Chandler 1998: 166; Petersen 2001: 184; Michelsen 2004.

Egle cyrtacra Fan & Weng, 1982: 225 , 237, figs. 19, 20; Fan et al. 1988: 78, figs. 179, 182, 185; Dely-Draskovits 1993: 52; Xue et al. 1998: 660, fig. 1473; Hua 2006: 98. Synonymized by Michelsen (2004).

For further references, see Griffiths (2003).

Description. Very small, wing length 2.6–3.6mm.

Male. Parafacial in middle narrower than postpedicel. Lower facial margin projected slightly beyond level of fronto-parafacial angle. Genal setae in two irregular rows. Prealar seta same length as or slightly longer than posterior notopleural seta. Proepisternals 1; proepimerals (1–)2. Scutellum sometimes without usual minute setulae beneath tip. Lower calypter very short, weakly convex at hind margin. Submedian tibial setae: fore tibia with 0 ad- and 1–2 fine p–pv-setae; mid tibia with 0 ad-, 2 pd- and 0–2 short p-setae; hind tibia with 3–8 short av- and some short p–pv-setae before middle. Hind femur with short pv-setae on basal two-thirds. Tergite VI small, fused together with syntergosternite VII+VIII. Sternite V ( Figs. 132, 133 ) with posterior lobes characteristic, apically raised and furnished with a series of coarse setulae at rounded margin; a few short setae present postero-laterally on basal plate. Terminalia ( Figs. 134–137 ): shape of surstyli and cerci diagnostic.

Female. Prementum mat, extensively covered in thin dusting. Parafacial in middle narrower than postpedicel. Lower facial margin projected slightly beyond fronto-parafacial angle. Prealar seta nearly to fully as long as posterior notopleural seta. Proepisternals 1(–2); proepimerals (1–)2. Scutellum sometimes without usual minute setulae beneath tip. Lower calypter very short, weakly convex at hind margin. Submedian tibial setae: fore tibia with 0 ad- and 1–2 fine p–pv-setae; mid tibia with 1 ad-, 1–2 pd- and 0–1 short p-setae; hind tibia with 2–5 short av-setae. Oviscapt ( Figs. 191, 192 ): Sternites VI and VII extensively membranised on posterior two-thirds, at best a little sclerotized near hind margin of sternite VI; sternite VIII very reduced; small epiproct with a pair of short setulae; hypoproct rather complete, with 4–6 setulae at margins; cerci small, moderately slender. Spermathecae two normal-sized and cross-wrinkled, third spermatheca reduced in size and length of duct.

Material examined. DENMARK [ ZMUC]: S Jutland: Birkepøl, Als , 2 males 21.iv.1973; 1 male 7.v.1977 ( V. Michelsen). NE Zealand: Utterslev Mose, 1 male, 3 females 11.v.1981, 1 female, 13.v.1982, 1 male, 3 females 28–29.iv.2008 ( V. Michelsen); Smør- and Fedtmose, 1 female 13.v.1982, 1 male 1.v.1995, 4 females 23.iv.2008 ( V. Michelsen) . FINLAND [ FMNH]: Lapponia kemensis (W): Pallastunturi , 1 male (W.E. Hellén). Lapponia enontekiensis: Kilpisjärvi, 1 male, 1 female (W.E. Hellén); Saana, 2 males (W.E. Hellén, A.F. Nordman) NORWAY [ ZMUC]: Oppland (north): Fokstumyrin, ca. 1000m, 2 females 17.vi.1985 ( V. Michelsen). Sør-Trøndelag (inner): Kongsvoll , 900–1100m, 6 males, 7 females 12–20.vi.1985 ( V. Michelsen) . RUSSIA [ FMNH]: Murmansk Oblast: Vaitolahti , 1 female (W.E. Hellén); Petsamo [= Pechensky], 1 female 2.vii.1929 (H. Lindberg); Ponoj, 1 male (W.E. Hellén) ; SWEDEN [ MZUL, ZMUC]: Torne Lappmark: Abisko, 9 males 5 females 13.vi–11.vii.1951 (J. R. Vockeroth ), 2 females 9 & 18.vii.1957 (P.I. Persson ), 1 female 22.vi.1973, 1 male 8.vi.1975 (B.G. Svensson). Also seen from CANADA [ ZMUC]: Northwest Territories: Chesterfield, 1 male 12.vii.1950 (J.G. Chillcott); Tuktoyaktuk, 1 female 20–25.vi.1971 (D.M. Wood). Quebec: Payne Bay , 1 male 11.vii.1958 (E.E. MacDougall) .

Biology. In NW Europe ranging from temperate lowlands to the subarctic–arctic elevated and northern Fennoscandia. The Danish localities are fens with abundant thickets of Grey willow ( Salix cinerea L.), certainly one of the host plants for E. subarctica .

Distribution. A Holarctic species first described from northern Canada and Alaska by Huckett (1965), but Nearctic distribution recently summarized by Griffiths (2003) as USA: Alaska? Canada: Newfoundland, Northwest Territories, Quebec and Yukon. First recorded from Europe (British Isles, Denmark) by Ackland (1989), subsequently also from Norway, Sweden, Finland and adjacent northern Russia by Michelsen (2004). Further found in Austria and Switzerland by A. Grossmann (in litt.). Also occurring in China: Shanxi (Fan & Wang 1982; Hua 2006).

Relationships. Closely related to the following species, E. subarcticoides , described as new from Israel. For further details, see above under ‘The Egle subarctica species group’.

Figures

FIGURES 132–137. Egle subarctica, male terminalia. 132, 133. Sternite V, ventral and lateral views. 134, 135. Hypopygium, caudal and lateral views. 136. Pre- and postgonites, lateral view. 137. Phallus, lateral view. Same scale.

FIGURES 191–193. Egle spp., female terminalia. 191. E. subarctica, oviscapt, flat mounted. 192. Same, spermathecae. 193. E. subarcticoides, oviscapt, flat mounted [paratype: Israel]. Different scales.