Syzeuctus bicornis ( GRAVENHORST , 1829)

Riedel, Matthias, 2021, The genus Syzeuctus FÖRSTER in the Western Palaearctic region and Central Asia (Hymenoptera, Ichneumonidae, Banchinae), with descriptions of 17 new species, Linzer biologische Beiträge 52 (2), pp. 1013-1098 : 1025-1026

Syzeuctus bicornis ( GRAVENHORST, 1829) (Figs 26, 59, 102)

O r i g i n a l: Lissonota bicornis GRAVENHORST, 1829: 91 , type lost.

S t u d i e d m a t e r i a l: 43♀♀, 17♂♂; Austria, Czech Republic (Bohemia), France, Germany,

Sweden, Switzerland, United Kingdom. D e s c r i p t i o n: ♀: Body length 9.5-12 mm. Antenna with 38-42 flagellomeres ; 1st

flagellomere 4.0-4.6× longer than wide and 0.6× as long as eye; preapical flagellomere 1.3× longer than wide. Temple strongly and almost linearly narrowed behind eye, dorsally 0.4× as long as eye. OED 1.5-1.6× and OOD 1.7× ocellar diameter. Frons, vertex and occiput mainly smooth, with few punctures; frons with two paramedian horns. Face densely punctate, eye margins slightly divergent ventrally. Clypeus 1.5-1.6× wider than long, convex, with scattered punctures; apical margin rounded. MI 0.85-1.0. Genal carina reaching mandibular base.

Mesosoma with coarse dense punctures, 1.45× longer than high. Lateral pronotal groove smooth or partly rugose. Epicnemial carina low, with distinct tooth-shaped lamella on transversal part. Speculum ± punctate. Propodeum with complete apical transversal carina. Hind femur 4.7-4.9× longer than wide. Hind metatarsus 0.65-0.7× as long as hind femur. 2 nd hind tarsomere 1.4× longer than 3 rd one. Hind claw densely pectinate and moderately curved apically. Areolet stalked; 2 nd recurrent vein slightly distal to its middle. Nervulus postfurcal by 2× its width. Hairs on basal cell about as long as their intervals. Hind wing with 9 distal hamuli.

Metasoma slender; 1 st tergite 1.8-2.0× longer than wide, with scattered fine setiferous or sometimes coarser punctures laterally. 2 nd tergite 1.0-1.2× longer than wide, with fine scattered punctures. 3 rd tergite 1.0-1.3× longer than wide, densely but ± superficially punctate. Spiracles of 1 st to 3 rd tergites slightly protruding laterally. Ovipositor 2.0-2.1× longer than fore wing, 2.4× longer than metasoma and 4.3-4.4× longer than hind tibia.

Color: Black. Flagellum reddish-brown, basal flagellomeres infuscate. Clypeus yellowish in apical 2/3. Frontal and outer orbits with short narrow yellow stripes. Mesosoma black. 1 st to 3 rd tergites red, 4 th tergite only basally. Coxae and trochanters black; fore and mid legs reddish, tarsi ± infuscate; hind femur red, sometimes black; hind tibia and hind tarsus ± black. Wings hyaline or slightly brownish infuscate, without apical spots;

pterostigma brown. ♂: Body length 10 mm. Antenna with 38-41 flagellomeres; 1st flagellomere 4.4× longer

than wide and 0.64× as long as eye. Head and mesosoma with rather long erected hairs (as long as ocellar diameter). Temple moderately and roundly narrowed behind eye, dorsally c. 0.75× as long as eye. OED 1.8-2.1× and OOD 2.6× ocellar diameter. Frons with two paramedian horns, strongly impressed medially. MI 1.0. Genal carina reaching mandibular base. Epicnemial carina low, but with dentiform lamella on transversal part. Propodeum with distinct apical transversal carina. Hind femur 4.5-5.0× longer than wide. Areolet stalked; 2 nd recurrent vein in or slightly proximal to its middle. Nervulus slightly postfurcal by 1× its width. Basal cell densely pilose.

1 st tergite c. 2× longer than wide, almost smooth. 2 nd tergite 1.05-1.15× longer than wide, with rather dense punctures. 3 rd tergite 1.05-1.15× longer than wide, with dense but rather superficial punctures.

Color: Black. Flagellum reddish. Mandible except teeth, clypeus, face (sometimes with black paramedian stripes), gena, often outer and frontal orbits, scape ventrally, often tegula, spot on subtegular ridge, and part of propleuron yellow. Sometimes mesosoma entirely black. Fore and mid coxae frontally and fore and mid legs except reddish dorsal stripes yellow. 1 st to 4 th tergites red; 1 st tergite black basally. Hind femur black or red and narrowly infuscate apically or brown; hind tibia yellow basally, brown apically; hind tarsus brown. Wings hyaline, pterostigma brown.

Hosts unknown.