Syzeuctus hyalinipennis SZÉLIGETI, 1901

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 : 1044-1045

Syzeuctus hyalinipennis SZÉLIGETI, 1901 , new ♂ (Figs 35, 72)

O r i g i n a l: Syzeuctus hyalinipennis SZÉPLIGETI, 1901: 143

H o l o t y p e: (♀) "Transbaikalia Burdukova; Exp Zichy leg. Csiki " (Budapest), type studied .

S t u d i e d m a t e r i a l: 1♀ and 3 ♂♂; Mongolia and Far East Russia.

D e s c r i p t i o n: ♀: Body length 9.5 mm. Tips of flagella missing; 1 st flagellomere 5.0× longer than wide and 0.62× as long as eye. Temple strongly and roundly narrowed behind eye, dorsally c. 0.4× as long as eye. OED 1.75× and OOD 2.1× ocellar diameter. Frons densely punctate, slightly impressed medially. Face densely punctate, inner eye margins slightly convergent ventrally. Clypeus 2.0× wider than long, almost smooth, apical margin rounded. MI 0.6. Upper mandibular tooth larger than lower one. Genal carina reaching mandibular base.

Mesosoma 1.4× longer than high. Frontoventral edge of pronotum moderately curved; lateral pronotal groove smooth. Speculum punctate. Epicnemial carina low, with blunt slightly denticular lamella on transversal part, low on pleural part. Propodeum with dense punctures, apical transversal carina complete. Hind femur slender, 5.9× longer than wide. Hind metatarsus 0.65× as long as hind femur. 2 nd hind tarsomere 1.5× longer than 3 rd hind tarsomere. Hind claw pectinate, moderately curved apically. Areolet stalked; 2 nd recurrent vein slightly distal to its middle. Nervulus postfurcal by 2× its width. Hairs on basal cell longer than their intervals. Hind wing with 8 distal hamuli.

Metasoma slender. 1 st tergite 1.95× longer than wide, with dense, coarse punctures laterally. 2 nd tergite 1.2× longer than wide, with dense, coarse punctures. 3 rd tergite 1.15× longer than wide, with dense punctures. Spiracles of 1 st to 3 rd tergites slightly protruding laterally. Ovipositor 0.95× as long as fore wing, 1.3× longer than metasoma and 2.0× longer than hind tibia.

Color: Black. Clypeus reddish in apical 2/3. Narrow stripe of frontal orbits yellow, slightly widened dorsally. Mesosoma including tegula entirely black. 1 st to 3 rd tergite entirely and 4 th tergite basally red. Coxae and trochanters black; fore and mid legs otherwise reddish; hind leg dark brown; hind tibia ochreous in basal 0.2. Fore wing hyaline; pterostigma brown.

♂ ( Mongolia): Body length 9-10 mm. Head and mesosoma with rather long erected hairs. Antenna with 41 flagellomeres; 1 st flagellomere 4.8× longer than wide and 0.62× as long as eye. OED 1.1-1.5× and OOD 1.6-2.2× ocellar diameter. Temple strongly and roundly narrowed behind eye, dorsally 0.6× as long as eye. Clypeus 1.5-1.6× wider than long, convex. MI 0.6-0.7. Lateral pronotal groove partly rugose. Epicnemial carina low, with ± distinct tooth opposite to ventral edge of pronotum. Speculum punctate. Apical carina of propodeum strong and complete. Hind femur 5.3× longer than wide. Hind metatarsus 0.7× as long as hind femur. 2 nd hind tarsomere 1.3× longer than 3 rd one. Claws with basal teeth, moderately bent apically. Areolet stalked; 2 nd recurrent vein in or distal to its middle. Nervulus postfurcal by 2× its width. Hairs on basal cell longer than their intervals. Hind wing with 8 distal hamuli.

1 st tergite 1.8-2.1× longer than wide, with scattered fine or rather coarse punctures. 2 nd tergite 1.15-1.25× longer than wide, with rather dense coarse punctures. 3 rd tergite 1.1- 1.2× longer than wide, with dense punctures, sometimes superficial punctures. Spiracles of 1 st to 3 rd tergites protruding laterally.

Color: Black. Flagellum blackish. 1 st tergite often red apically. 2 nd to 4 th tergites red. Palps, mandible except teeth, clypeus, face except black median stripe, inner and outer orbits, sometimes ventral spot on scape, tegula, sometimes apical spots on scutellum and postscutellum yellow. Fore and mid legs with coxae and trochanters yellow, mid coxa with black dorsal spot; hind femur reddish or black and yellow apically; hind tibia yellow, apical 1/2-2/3 brown; mid and hind tarsi ± brown. Wings hyaline, without brown apical spots, pterostigma brown.

Hosts unknown.

R e m a r k: This species is closely related to S. petiolaris (GRAVENHORST) . The ♀ differs from the European material of S. petiolaris by slenderer basal tergites and blackish hind legs. It is not clear yet, if these Mongolian ♂♂ (coll. Budapest) which were determined as " S. apicalis " by MOMOI and described here in detail, belong to the ♀ from Far East Russia. There seem to be several closely related taxa of the petiolaris- species group in Central and Eastern Asia ; for a better knowledge, more material from these areas has to be studied in the future.