Foersterella fuscicornis, 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 : 565-566

Foersterella fuscicornis sp. nov.

Figs 4 , 10

Material. Holotype male labeled “ SWEDEN: Öland, Bostorpsvägen, 56°38′ 56.8N 16°35′ 25.5E, 25.vi.2014, C. Hansson”, in MZLU. Paratypes (6♂): 1♂ “ SWEDEN: Öland, Bårby Borg, 56°30′ 09.0N 16°25′ 33.1E, 1.vii.2014, C. Hansson” ( MZLU); 2♂ “ SWEDEN: Öland, Karums Alvar, 56°46′ 28.1N 16°37′ 30.6E, 4.vii.2014 ” ( BMNH, MZLU); 1♂ “ FRANCE: B du Rhone, Fonscolombe (3), 18.vii.1979, M.W.R. de V. Graham” ( BMNH); 1♂ from same locality as previous but collected 25.vii.1979 ( BMNH); 1♂ “ FRANCE: (Ht Rhin), Wintzenheim, on Tanacetum vulgare, 27.vii.1974, Remaudiere” ( BMNH).

Diagnosis. Male. Antenna ( Figs 4 , 10 ): flagellum completely dark; F1 1.5×, F2 1.3×, F3 1.2×, and F6 0.7× as long as wide; antennal clava (in widest part) 1.3× as wide as greatest width of pedicel; face with rather thin setation, as in F. angusticornis ( Fig. 5 ).

Description (male holotype, a non-shrivelled specimen). Length: 1.2 mm.

Colour. Scape yellowish-white, pedicel and flagellomeres dark brown. Head and mesosoma golden-green, gaster dark brown with golden-green tinges. Fore coxa yellowish white with base infuscate, mid coxa yellowishbrown with base infuscate, hind coxa dark brown with metallic tinges; tibiae pale yellowish-brown with bases more or less infuscate; tibiae pale 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: 1.5/1.3/1.2/1.0/0.8/0.7. Frons and vertex with very weak and superficial reticulation; occipital margin rounded without carina. Ratios width/height/length of head 1.9/1.0/1.5; height of eye/malar space/mouth opening 1.5/1.0/1.3; distances between posterior ocelli (POL)/between ocelli and eyes (OOL) 1.8/1.0.

Mesosoma. Mesosoma 1.5× as long as wide. Pronotum medially 1.2× 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 0.9× 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 the middle and posterior pair ⅔ from anterior margin of scutellum. Fore wing 2.6× as long as wide; submarginal vein with three setae on dorsal surface; speculum small and closed below; basal cell covered with setae; costal cell narrow, 14× as long as wide, with a complete row of 9 setae on ventral surface; ratios of length of marginal/ postmarginal/stigmal veins 5.3/3.3/1.0. Propodeum steeply sloping; median part with 6+6 short setae on either side of an imaginary median line and setae pointing towards the imaginary median line; propodeal callus with eight setae.

Metasoma. Petiole very short and inconspicuous. Gaster ovate, 1.7× as long as wide. Ratio length of mesosoma/length of gaster 0.8.

Variation. Minimal in the paratype material, the length varies from 0.9–1.1 mm; in one Swedish specimen the mid coxa is dark brown, and the median part of the propodeum has 5+5 setae in another Swedish specimen and 8+8 setae in one French specimen.

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. France, Sweden.

Etymology. Named after the completely dark 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.