Mesochorus riparius SCHWENKE, 1999

Riedel, Matthias, 2018, The types of Mesochorus GRAVENHORST (Hymenoptera, Ichneumonidae, Mesochorinae) described by W. SCHWENKE and deposited in the Senckenberg Deutsches Entomologisches Institut, Beiträge Zur Entomologie = Contributions to Entomology 68 (1), pp. 1-29 : 13

22. Mesochorus riparius SCHWENKE, 1999

( Figs 21a–d )

Holotype: "() Dessau 4 km SSW 19.9.85 K.H. Zoerner " [, without no., Germany: Saxony-Anhalt, 4 km SSW of the district Dessau of town Dessau-Rosslau , 19.9.1985, leg. K.H. Zoerner] ( SDEI).

Description: Missing: Left flagellomeres from 23 th on and right flagellomeres from 25 th on. Body length 4.1 mm. 1 st flagellomere 6.2x longer than wide and 0.63x as long as the eye; 2 nd flagellomere 4.0x longer than wide. Temple very short and very strongly narrowed behind eye, only 0.2x as long as the eye width. Ocelli very large, OOD 0.4. Face narrow, coarsely punctate, sides convergent ventrally, 0.86x as wide as the length of clypeus+face and 0.65x as wide as the length of the eye. Clypeus smooth centrally. Facial orbit completely, base of mandible and malar space striate. MI 0.2. Mandible with two equal teeth. Genal carina reaching the hypostomal carina far from mandibular base. Mesoscutum with dense but superficial punctures; mesopleuron with fine dense punctures dorsally and with fine scattered punctures ventrally; metapleuron with very fine scattered punctures. Area basalis trapezoid, about as long as wide; area superomedia 2.3x longer than wide and 1.25x longer than the area petiolaris, costula in frontal 4/10 of length of area superomedia; area petiolaris about as long as wide. Hind femur 4.4x longer than wide; hind metatarsus 0.45x as long as the hind tibia; hind claws with three or four rather long teeth. Areolet pointed, oblique, 2 nd recurrent vein slightly proximal to its middle; nervulus interstitial; pterostigma 3.0x longer than wide, radial vein in its distal 0.65. 1 st tergite 2.5x longer than wide; postpetiolus 1.4x longer than wide, with coarse longitudinal striae; 2 nd tergite about as long as wide; thyridium very large, transversal-oval. Ovipositor sheath pilose, 7.7x longer than wide and 0.92x as long as the hind metatarsus, slightly narrowed in the apical 4/10 of tibial length.

Colour: Black. Flagellum yellowish, slightly darkened apically. Head reddish; face and clypeus brown, more blackish centrally; orbits yellow-red; frons medially, ocellar field and occiput blackish. Mesosoma black; pronotum reddish-brown, upper margin yellowred; tegula brownish, wing base yellow; mesoscutum with H-shaped central reddish spot. Metasoma black; 2 nd tergite reddish-yellow in the apical 2/10 of tibial length; 3 rd tergite reddish-yellow in the basal 0.5, brown laterally and apically; following tergites black. Legs reddish-yellow; hind coxa brown; hind femur reddish; hind tibia cream-yellow, brownish in the apical 1/10 of tibial length (0.5x of tibial width). Pterostigma hyaline.

Remark: This species is correctly placed in the key of the pectoralis -group ( SCHWENKE, 1999: 95–98) and is characterized by its narrow face, large ocelli and striated postpetiolus.

Figures

Fig. 21a-d: Holotype of Mesochorus riparius SCHWENKE:a. face; b. mesosoma; c. metasoma; d. ovipositor sheath.