Egle brevicornis ( Zetterstedt, 1838 )

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 : 25-27

5. Egle brevicornis ( Zetterstedt, 1838)

Figs. 29 , 63–68 , 78, 79 .

Anthomyza brevicornis Zetterstedt, 1838: 683 .

Hylemyia (Egle) brevicornis (Zetterstedt) ; Ringdahl 1933: 29; Ringdahl 1939b: 140.

Egle brevicornis (Zetterstedt) ; Tiensuu 1936: 14; Karl 1943: 74; Karl 1944: 84; Ringdahl 1952: 176; Ringdahl 1959: 271, fig. 100; Hennig 1967a: 139, plate figs 134, 147; Ackland 1970: 187, 192; Hennig 1976: 937; Michelsen 1976:

71; Hackman 1980: 132; Michelsen 1985: 42; Draber-Moṅko 1991: 234; Dely-Draskovits 1993: 51; Chandler 1998: 166; Michelsen & Merz 1998: 314; Petersen 2001: 184; Michelsen 2004.

For further references, see Bezzi & Stein (1907).

Taxonomic note. European authors before Ringdahl (1933) did not distinguish between the two species presently known as E. ciliata (Walker) and E. brevicornis (Zetterstedt) and used either of the names muscaria and brevicornis for them.

Description. Resembling Egle ciliata but separated in both sexes as follows: Smaller, wing length 3.5–4.9mm. Head ( Fig. 29 ) distinctly higher than long. Parafacial about same width throughout, not distinctly widened downwards. Lower facial margin less projected in front of fronto-parafacial angle. Haustellum and palp not so strikingly long. Lower calypter shorter than upper calypter. Proepisternals fewer, (1–)2(–3). Fore tibia without pd-setae. Male: Chaetotaxy of head, body and legs less proliferous than in E. ciliata . Frons on upper part broader than diameter of anterior ocellus and with broader, narrowly separated parafrontals. Proepimerals fewer, 4–10. Mid tibia often with 1 short ad-seta. Terminalia ( Figs. 63–68 ): Shape of surstyli and cerci very different from E. ciliata ; very similar to E. anderssoni but apical extension of cerci and in particular surstyli proportionately longer. Female. Oviscapt ( Figs. 78, 79 ): Hind marginal setulae on tergite VIII uni-serial; pair of fine setae absent on hind part of sternite VIII; cerci moderately wide, rather parallelsided in broadest aspect, rounded at apex.

Material examined. DENMARK [ ZMUC]: E Jutland: Anholt Is., 1 male, 1 female 21–22.v.1973 ( V. Michelsen). W Jutland: Ulfborg Skovdistrikt, 1 male, 1 female 5-8.vi.1980 (S. Andersen & V. Michelsen); Isen Bjerg, Gludsted Plantage, on male Salix repens 1 male, 1 female 28.iv.2004, 1 female 25.iv.2005, on female Salix repens 2 males 3 & 14.v.2005 (Y. Dupont) . FINLAND [ FMNH]: Lapponia kemensis (W): Muonio , 1 male (W.E. Hellén) . SWEDEN [ MZUL, ZMUC]: Skåne: Ängelholm , 3 males 25.iv.1948 (O. Ringdahl) .

Biology. In England (D.M. Ackland in litt.) and Denmark mainly found on Creeping willow ( Salix repens L.), a low-growing shrub found in wet and dry sand dune slacks, on acid heaths and moorland. Other species of willow must support the species in northern Fennoscandia.

Distribution. Only known with certainly from central and northern Europe. Huckett (1965) indeed recorded E. brevicornis from Alaska ( USA) and Manitoba ( Canada), but Griffiths (2003) showed that this was based on misidentifications of two similar species endemic to the Nearctic Region. Found in British Isles ( Ackland 1970), Denmark ( Michelsen 1976), Finland ( Tiensuu 1936), Latvia ( Hennig 1967a), Poland ( Karl 1943), Sweden ( Ringdahl 1952), Switzerland ( Michelsen & Merz 1998). Records from Belgium ( Gosseries & Ackland 1991) and Hungary ( Darvas et al. 2001; Darvas 2001) are based on old determinations and refer probably to E. ciliata .

Relationships. The Nearctic E. washburni is externally practically impossible to separate from E. brevicornis , but the male surstyli of the former are more slender in profile and basally curved inward in rear view. The very similar male terminalia suggest that E. anderssoni is also closely related.

Figures

FIGURES 27–30. Egle spp., male head. 27. E. concomitans. 28. E. ciliata. 29. E. brevicornis. 30. E. anderssoni. Same scale.

FIGURES 63–68. Egle brevicornis, male terminalia. 63, 64. Sternite V, ventral and lateral views. 65, 66. Hypopygium, caudal and lateral views. 67. Pre- and postgonites, lateral view. 68. Phallus, lateral view. Same scale.

FIGURES 75–81. Egle spp., female terminalia. 75. E. ciliata, oviscapt, flat mounted. 76, 77. Same, distal oviscapt, lateral and laterodorsal views. 78, 79. E. brevicornis, distal oviscapt, lateral and laterodorsal views. 80, 81. E. anderssoni [paratype: Sweden], distal oviscapt, lateral and laterodorsal views. Same scale for 76–81.