Egle inermis Ackland, 1970

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 : 40-43

12. Egle inermis Ackland, 1970

Figs. 115–120 , 184 .

‘ Hylemyia (Egle) parvaeformis (Schnabl) ’; Ringdahl 1933: 29. Misidentification.

‘ Egle parvaeformis Schnabl’; Karl 1934: 92, fig. 1; Tiensuu 1936: 14; Karl 1937: 139; Ringdahl 1952: 178; Ringdahl 1959: 272, fig. 138; Hackman 1980: 132. Misidentification.

‘ Egle steini Schnabl’; Hennig 1967b: 147, plate figs. 136, 144, 152; Teschner 1999: 131; Wei et al. 1998: 661, fig.1480; Hua 2006: 98. Misidentification.

Egle inermis Ackland, 1970: 188 , figs. 3, 5, 8; Hennig 1976: 938, 939; Dely-Draskovits 1993: 52; Ackland 2003: 84; Michelsen 2004; Komzáková 2006.

‘ Egle bicaudata (Malloch) ’; Ackland 1989: 220; Chandler 1998: 166; Grossmann 2000: 177; Michelsen & Barták 2001: 457, 460; Petersen 2001: 184. Misidentification.

For further references, see Griffiths (2003).

Description. Very small, wing length 2.7–3.3 mm.

Male. Subgena mat, covered in thin dusting. Parafacial in middle narrower than postpedicel. Lower facial margin reaching slightly beyond fronto-parafacial angle. Genal setae in two irregular rows. Prealar seta about two-thirds as long as posterior notopleural seta. Notopleuron without accessory setulae. Proepisternals 1; proepimerals 1–2. Lower calypter much shorter than upper calypter, forming a shallow lobe. Submedian tibial setae notably few: fore tibia with 0–1 long and fine pd- and 0 p-setae; mid tibia with 0(–1) ad-, 1 pd- and 0 psetae; hind tibia with 0 av- and 0 p–pv setae. Hind femur with short pv-setae on basal two-thirds. Tergite VI separated from syntergosternite VII+VIII. Sternite V ( Figs. 115, 116 ) diagnostic in respect to shape and setation of posterior lobes; setal tufts postero-laterally on basal plate consisting of 7–9 setae and setulae. Terminalia ( Figs. 117–120 ): shape of cerci and surstyli diagnostic.

Female. Prementum and subgena mat, covered in thin dusting. Parafacial in middle narrower than postpedicel. Lower facial margin reaching slightly beyond fronto-parafacial angle. Prealar seta two-thirds as long to same length as posterior notopleural seta. Notopleuron without accessory setulae. Proepisternals 1; proepimerals 1–2. Lower calypter much shorter than upper calypter, forming a shallow lobe. Submedian tibial setae: fore tibia with 0–1 fine pd- and 0 p-setae; mid tibia with 1 ad-, 1 pd- and 0 p-setae; hind tibia without av-setae. Hind femur without pv-setae basally. Oviscapt ( Fig. 184 ): Sternites VI and VII relatively broad and well maintained on posterior parts. Sternite VIII absent. Epiproct bare or with pair of fine setulae; hypoproct deeply incised basally, only maintained as a marginal strip, with 0–2 minute apical setulae. Cerci moderately slender, tapering on projecting apices. Two spermathecae normal-sized, subglobular with weak cross-striae, one spermatheca more or less reduced in size and with shortened duct.

Material examined. CZECH REPUBLIC [ ZMUC]: Ústi nad Labem: Bílina-Holibka , near pond, 420m, 1 female 28-30.iv.1998 (M. Barták) . Moravia-Silesia: Beskydy-Muřinkový , peat-bog, 950m, 1 female 8.v.1988 (M. Barták) . DENMARK [ ZMUC]: NE Zealand: Lyngby Mose , 1 male 21.v.1922, 1 male, 2 females 31.v.1922 (W. Lundbeck) . FINLAND [ FMNH]: Nylandia: Helsinki , 1 male 7.v.1938 (L. Tiensuu). Lapponia inarensis: Utsjoki, 1 male ( R. Frey), 1 male 16.vi.1948 (E. Thuneberg) . NORWAY [ ZMUC]: Sør-Trøndelag (inner): Kongsvoll , 900–1100m, 4 males, 2 females 12–20.vi.1985 ( V. Michelsen). Southern Nordland (outer): Storglomvatn , 4 males 29.vi.1948, 1 male 2.vii.1948 ( T. Soot-Ryen) . SWEDEN [ MZUL, ZMUC]: Skåne: Hälsingborg, 3 males 1 female 4.vi.1927 (O. Ringdahl); Söderåsen , 1 male 13.v.1926; Råå, 2 males, 2 females 3.vi.1922, 4 males, 2 females 28.v.1926 (O. Ringdahl) . Jämtland: Åre, 1 female 7.vi.1948, 1 male 12.vi.1948, 1 female 15.vi.1948 (H.C. Huckett). Torne Lappmark: Abisko , 1 female 18.vi.1951 (J. R. Vockeroth); Stordalen, Abisko, 1 female 26.vi.1957 (P.I. Persson); Abisko, 1 female 10.vi.1975 (B.G. Svensson). Nearctic specimens seen from : CANADA [ ZMUC]: Manitoba: Carberry , 2 males 16.v.1953 (Brooks & Kelton) . Yukon Territory: Rampart House , 1 male 5.vi.1951 (J.E.H. Martin) .

Biology. Karl (1934) noticed an adult preference for Bay willow ( Salix pentandra L.), a comparatively late-flowering willow. Hennig (1967b) recorded the present species, then misidentified as Egle steini , as being reared from S. pentandra in Poland.

Distribution. A widespread Holarctic species, but it was first recognized as distinct from other, similar species by Ackland (1970). Its wide occurrence in the boreal to low arctic parts of North America was first documented by Griffiths (2003), who also showed that E. bicaudata (Malloch, 1920) is an endemic Nearctic species replacing E. inermis in southern Alberta to southern California and eastwards to Illinois. Egle inermis , in part misidentified as E. bicaudata , has now been recorded from the following European countries, British Isles ( Ackland 1970), Denmark ( Petersen 2001), Czech Republic ( Michelsen & Barták 2001), Germany ( Grossmann 2000), Poland ( Hennig 1976) and recently also from Finland, Norway and Sweden ( Michelsen 2004).

Relationships. The male terminalia are overall very similar in the Nearctic E. bicaudata (Malloch, 1920) , but the two species differ in the shape of the apical extension of the cerci and the surstyli as seen in profile; see Griffiths (2003: 2348, figs. 2668–2664). The following species, E. inermoides from Spain, is also very close (see Relationships under that species).

Figures

FIGURES 115–120. Egle inermis, male terminalia. 115, 116. Sternite V, ventral and lateral views. 117, 118. Hypopygium, caudal and lateral views. 119. Pre- and postgonites, lateral view. 120. Phallus, lateral view. Same scale.

FIGURES 184–186. Egle spp., female terminalia. 184. E. inermis, oviscapt, flat mounted. 185. E. inermoides, oviscapt, flat mounted [paratype: Spain]. 186. Same, spermathecae. Different scales.