Foersterella angusticornis, Hansson, Christer, 2016

Hansson, Christer, 2016, The European species of Foersterella Dalla Torre (Hymenoptera: Tetracampidae), including the description of two new species, Zootaxa 4137 (4), pp. 561-568 : 562-565

Foersterella angusticornis sp. nov.

Figs 1, 5 , 9

Material. Holotype male labeled “ SWEDEN: Skåne, Kranke, Ekskogen, 55°41′ 10.3N 13°27′ 40.2E, 11.vii.2014, C. Hansson”, in MZLU. Paratypes (7♂): 6♂ collected in Sweden: Närke, Örebro, Adolfsberg, by Anton Jansson, with collecting dates: 23.viii.1956 ( MZLU), 16.ix.1956 ( MZLU), 22.vii.1957 ( MZLU), 4.viii.1957 ( BMNH), 16.viii.1957 ( MZLU), 29.viii.1957 ( MZLU); 1♂ “ Sweden: Närke, Örebro, 19.viii.1955, A. Jansson” ( BMNH).

Diagnosis. Male. Antenna ( Figs 1 , 9 ): antennal flagellum slender, e.g. F1–3 each 2.2× as long as wide, and F6 1.3× as long as wide; antennal clava (in widest part) 0.9× as wide as greatest width of pedicel; F1–3, F6, and clava dark brown, F4 and F5 white; face with rather thin setation ( Fig. 5 ); fore femur predominantly dark brown ( Fig. 1 ).

Description (male holotype, a non-shrivelled specimen). Length: 1.1 mm.

Colour. Scape yellowish-white, pedicel pale brown with dorsal part darkened, F1–3, F6, and clava dark brown, F4 and F5 white. Head, mesosoma and gaster golden-green. Fore coxa yellowish-white with base infuscate, mid coxa yellowish-brown with base infuscate, hind coxa with basal ⅓ dark brown with golden-green tinges and apical ⅔ yellowish-brown; fore tibia dark brown with apical ¼ yellowish-brown, mid and hind femora yellowish-brown; tibiae yellowish-brown; tarsi with tarsomeres 1–3 yellowish-brown and tarsomere 4 pale brown. Wings hyaline.

Head. Scape 2.0× as long as wide; ratios length/width of flagellomeres I/II/III/IV/V/VI: 2.2/2.2/2.2/1.8/1.4/1.3. Frons and vertex with very weak and superficial reticulation; occipital margin rounded without carina. Ratios width/height/length of head 1.9/1.4/1.0; height of eye/malar space/mouth opening 2.0/1.0/1.4; distances between posterior ocelli (POL)/between ocelli and eyes (OOL) 1.7/1.0.

Mesosoma. Mesosoma 1.5× as long as wide. Pronotum medially 1.6× as long as midlobe of mesoscutum. Mesoscutum 0.7× as long as scutellum, with very weak and fine reticulation and short setae scattered over surface; midlobe with two long setae close to posterior margin; notauli complete and deep. Scutellum 1.1× as long as wide, with very weak and fine reticulation and two pair of setae attached close to lateral margin, the anterior pair about in middle and posterior pair ⅔ from anterior margin of scutellum. Fore wing 2.6× as long as wide; submarginal vein with four setae on dorsal surface; speculum small and closed below; basal cell covered with setae; costal cell narrow, 13× as long as wide, with a complete row of 11 setae on ventral surface; ratios of length of marginal/ postmarginal/stigmal veins 7.5/4.4/1.0. Propodeum steeply sloping; median part with 10+10 setae on either side of an imaginary median line and setae pointing towards the imaginary median line; propodeal callus with 14 setae.

Metasoma. Petiole very short and inconspicuous. Gaster ovate, 1.3× as long as wide. Ratio length of mesosoma/length of gaster 1.0.

Variation. Minimal in the paratype material, the length varies from 0.9–1.1 mm, and in one specimen the fore coxa is yellowish-brown.

Female. Unknown.

Host. Unknown, but based on records for other species in Foersterella it probably is an egg parasitoid of some species of Cassida ( Coleoptera : Chrysomelidae ).

Distribution. Sweden.

Etymology. Named after the comparatively slender antennal flagellum in the male.

Figures

FIGURES 1 – 6. 1 – 4, Foersterella spp., habitus in lateral view: 1, F. angusticornis sp. nov., male holotype, specimen length 1.1 mm; 2, F. erdoesi Bouček, male non-type from Sweden (Skåne), specimen length 1.3 mm; 3, F. reptans (Nees), male non-type from Sweden (Skåne), specimen length 1.1 mm; 4, F. fuscicornis sp. nov., male holotype, specimen length 1.2 mm. 5 & 6. Head, frontal view, males: 5, F. angusticornis, holotype; 6. F. erdoesi, non-type from Sweden (Skåne).

FIGURES 7 – 13. Foersterella spp. 7 – 10, antenna, lateral view, male: 7, F. erdoesi Bouček; 8, F. reptans (Nees); 9, F. angusticornis sp. nov.; 10, F. fuscicornis sp. nov. 11, Foersterella sp., female, head and antennae, lateral view. 12 & 13, gaster, dorsal view, female: 12, Foersterella sp.; 13, F. erdoesi.