Mesochorus flexus 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 : 6

8. Mesochorus flexus SCHWENKE, 1999

( Figs 8a–d )

Holotype: "() Dessau 4,5 km NW, 21.6.88 H. Zoerner " [, without no., Germany: Saxony-Anhalt, 4.5 km NW of the district Dessau of town Dessau-Rosslau , 21.6.1988, leg. K.H. Zoerner] ( SDEI?).

The holotype is missing in the material from the SDEI and has not been found in the ZSM or in the HORSTMANN collection either. Although SCHWENKE (1999: 40) stated paratypes from the same locality, they were not found in the available material (probably he confused the localities of his material) .

Paratype: "() Oppach 1.2 km O 10.6 .1993 171/93 H. Zoerner " [, no. 171/93, Germany: Saxony, 1.2 km E of Oppach, 10.6.1993, leg. K.H. Zoerner] ( ZSM) .

Description: Complete. Body length 2.8 mm. Flagellum with 25 flagellomeres; 1 st flagellomere 6.7x longer than wide and 0.58x as long as the eye; 2 nd flagellomere 4.2x longer than wide; preapical flagellomeres ca. 2.0x longer than wide. Temple slightly narrowed behind eye, 0.8–0.9x as long as the eye width. OOD 1.8. Face 1.2x wider than the length of clypeus+face and about as wide as the length of eye, sides parallel, with superficial punctures. MI 0.8. Whole facial orbit and malar space striate. Mandible with two equal teeth. Genal carina reaching the hypostomal carina far from mandibular base. Mesoscutum with fine superficial punctures; mesopleuron with moderately coarse, superficial punctures dorsally and almost smooth ventrally; metapleuron with superficial punctures. Area basalis trapezoid, slightly wider than long; area superomedia 1.6x longer than wide and 0.9x as long as the area petiolaris, costula in frontal 4/10 of length of area superomedia; area petiolaris 1.1x longer than wide. Hind femur 4.4x longer than wide; hind metatarsus 0.47x as long as the hind tibia. Areolet pointed, 2 nd recurrent vein in its middle; nervulus slightly postfurcal (0.5x of its width); pterostigma 2.7x longer than wide, radial vein in its distal 0.57, distal parts of radial vein distinctly sinusoid. 1 st tergite 2.7x longer than wide; postpetiolus 1.2x longer than wide, smooth; 2 nd tergite 0.85x as long as wide; thyridium comma-shaped, oblique. Ovipositor sheath with scattered hairs in apical half, 8.6x longer than wide and about as long as the hind metatarsus, in apical 2/3 with concavely narrowed dorsal margin, strongly narrowed ventrally.

Colour: Blackish. Scape and flagellum ochreous basally, brownish in apical 3/4. Face reddish-yellow, slightly darker below antennae; orbit, wide gena, malar space and mandible except teeth reddish-yellow. Mesosoma brown; tegula and wing base yellowish. Metasoma blackish; 1 st sternite completely and 1 st tergite dark reddish basally; 2 nd tergite with narrow yellow band in the apical 2/10 of tibial length; 3 rd tergite with yellow band in the basal 0.2. Legs reddish-yellow; hind tibia cream-yellow, ochreous in apical 1.5/10 of tibial length (1x of tibial width). Pterostigma hyaline.

Remark: This species runs to Mesochorus frondosus SCHWENKE in his key for the curvulus -group ( SCHWENKE, 1999: 35–37) because the pronotum is blackish as the rest of the mesosoma. It can be differentiated from other members of the curvulus -group by the characteristic form of the ovipositor sheaths.

Figures

Fig. 8a-d: Paratype of Mesochorus flexus SCHWENKE:a. face; b. mesosoma; c. habitus; d. ovipositor sheath.