Syzeuctus irrisorius ( ROSSI , 1794)

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 : 1048-1049

Syzeuctus irrisorius ( ROSSI, 1794) (Figs 75, 119)

O r i g i n a l: Ichneumon irrisorius ROSSI, 1794: 108 , type lost.

S t u d i e d m a t e r i a l: 34♀♀, 30♂♂; Austria, Corsica, Croatia, Czech Republic (Moravia), France, Germany, Greece *, Hungary, Italy, Sardinia *, Slovakia, Spain, Turkey .

D e s c r i p t i o n: ♀: Body length 7.5-10(12) mm. Antenna with 32-38 flagellomeres; 1 st flagellomere 3.8-4.7× longer than wide and 0.56× as long as eye; preapical flagellomere 0.9-1.0× as long as wide. Temple strongly and roundly narrowed behind eye, dorsally c. 0.45× as long as eye. OED 1.3-1.6× and OOD 2.1× ocellar diameter. Frons densely punctate, slightly impressed medially. Face densely punctate. Clypeus 1.5× wider than long, with scattered punctures, apical margin rounded. MI 0.8-0.9. Genal carina sometimes reaching hypostomal carina close to mandibular base, usually reaching mandibular base.

Mesosoma with coarse dense punctures, 1.30-1.35× longer than high. Frontoventral edge of pronotum strongly curved; lateral pronotal groove smooth. Epicnemial carina slightly elevated, more distinctly on transversal part, carina on pleural part distinct. Speculum partly smooth. Propodeum with rather dense punctures; apical transversal carina entirely absent or shortly present laterally. Hind femur 5.1-5.2× longer than wide. Hind metatarsus 0.7× as long as hind femur. 2 nd hind tarsomere 1.5× longer than 3 rd one. Hind claw with rather short teeth, moderately bent apically. Areolet stalked; 2 nd recurrent vein distinctly distal to its middle. Nervulus postfurcal by 2× its width. Hairs on basal cell about as long as their intervals. Hind wing with 8 distal hamuli.

Metasoma stout. 1 st tergite 1.25-1.5× longer than wide, with scattered punctures laterally. 2 nd tergite 1.1-1.3× wider than long, with scattered or dense punctures. 3 rd tergite 1.15- 1.35× wider than long, with rather scattered or dense punctures. Ovipositor 0.8-1.1× as long as fore wing, 1.0-1.4× longer than metasoma and 2.1-2.9× longer than hind tibia.

Var.: A large ♀ from Spain (Bruxelles) has an unusually slender metasoma: body length 12 mm, 1 st tergite 1.45× longer than wide, with scattered punctures laterally. 2 nd tergite 1.1× longer than wide, with dense punctures. 3 rd tergite 1.1× longer than wide, with dense punctures. The specimen is otherwise typical.

Color: Black. Flagellum reddish, basal flagellomeres ± black. Palps, base of mandible, clypeus, gena and orbits yellow. Mesosoma black; spot on collare and upper margin of pronotum, anterolateral and central spots on mesoscutum, tegula, subtegular ridge, two spots on mesopleuron, spot on metapleuron and on upper division of metapleuron, scutellum except black anteromedian spot, postscutellum, spot anterior to propodeal spiracle and large triangular spot on posterior 2/3 of propodeum yellow. 1 st tergite with subbasal and apical yellow band; 2 nd to 4 th /5 th tergites with apical yellow bands. 2 nd and 3 rd tergites sometimes ± reddish. Coxae and trochanters black; hind coxa and trochanter black or hind coxa dorsally, trochanters and trochantelli partly yellow. Fore and mid legs yellow or red; mid tarsus ± brownish; hind femur red; hind tibia usually yellow basally, reddish-yellow apically; hind tarsus ± brownish. Fore wing without or with very weak

apical brown spot; pterostigma ochreous. ♂: Body length 7-9 mm. Antenna with 34-36 flagellomeres; 1st flagellomere 4.1× longer

than wide and 0.57× as long as eye; preapical flagellomere square. OED 1.4-1.5× ocellar diameter. MI 0.8-0.9. Frontoventral edge of pronotum strongly curved; lateral pronotal groove punctate. Epicnemial carina slightly elevated, more distinctly on transversal part, carina on pleural part distinct. Speculum partly smooth. Propodeum with rather dense punctures; apical transversal carina entirely absent or shortly developed laterally. Hind femur 5.0-5.3× longer than wide. Hind wing with 8-9 hamuli.

1 st tergite 1.5-1.7× longer than wide. 2 nd tergite 1.0-1.2× wider than long, densely punctate. 3 rd tergite 1.0-1.2× wider than long, densely punctate. 2 nd and 3 rd tergites with transversal thyridia at base.

Color: Similar to ♀. Flagellum reddish, basal flagellomeres infuscate. Clypeus reddish or yellow. 1st tergite with subbasal and apical yellow band; 2 nd to 5 th /6 th tergites with apical yellow bands. Coxae black, with yellow spots, trochanters with yellow spots, trochantelli usually yellow. Legs reddish; tarsi ± brownish. Wings without brown spot; pterostigma brownish.

Hosts unknown.