Mesochorus amnicolaris 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 : 3

2. Mesochorus amnicolaris SCHWENKE, 1999

( Figs 2a–d )

Holotype: "() Sebnitz 9 km N 8.8 .1993 283/93 H. Zoerner " [, no. 283/93, Germany: Saxony, 9 km N of Sebnitz, 8.8.1993, leg. K.H. Zoerner] ( SDEI).

Description: Missing: Both antennae. Body length 3.5 mm. Temple moderately and roundly narrowed, 0.75x as long as the eye width. OOD 1.5. Face punctate, about as wide as the length of face+clypeus and 0.9x the length of eye, with parallel sides. Ventral half of facial orbit and malar space widely striate. MI 0.3. Mandible with two equal teeth. Genal carina reaching the hypostomal carina far from mandibular base. Mesoscutum with fine scattered hair-punctures; mesopleuron with few fine punctures dorsally and with very scattered small hair-punctures ventrally; metapleuron almost smooth. Area basalis trapezoid, as long as wide; area superomedia short, almost diamond-shaped, 1.15x as long as wide and 0.8x as long as the area petiolaris, costula in frontal 4/10 of length of area superomedia; area petiolaris large, 1.25x longer than wide and ca. 0.4x as long as the propodeum. Hind femur 4.6x longer than wide; hind metatarsus 0.4x as long as the hind tibia; fore claws with some basal teeth. Areolet shortly stalked, 2 nd recurrent vein in its middle; nervulus slightly antefurcal; pterostigma wide, 2.8x longer than wide, radial vein in its distal 0.65. 1 st tergite 2.8x longer than wide, postpetiolus with some rugae; 2 nd tergite 0.86x as long as wide; thyridium comma-shaped. Ovipositor sheath stab-shaped, pilose (less densely apically), 9.3x longer than wide and 1.2x longer than the hind metatarsus, slightly narrowed over the whole length.

Colour: Black. Face reddish; facial orbit, mandible except teeth and malar space cream-yellow; gena and orbits otherwise reddish. Mesosoma blackish; pronotum reddish; hind edge of pronotum, tegula and wing base yellowish. Metasoma black; 2 nd tergite yellow in apical 1/10 of tibial length; 3 rd tergite yellow-red in basal 0.15 (slightly wider medially); following tergites blackish with indistinct dark-greyish hind margins. Legs yellowred, hind coxa more reddish; hind tibia yellow, narrowly infuscate in apical 1/10 of tibial length (0.5x of tibial width). Pterostigma hyaline-brownish.

Remark: The position of this species within the different species-groups sensu SCHWENKE (1999: 34) is questionable. The metasoma is mainly black with narrow pale bands on 2 nd and 3 rd tergites. It therefore can be placed in the angustatus -group where it runs to no. 35 ( Mesochorus tetricus sensu SCHWENKE non THOMSON: recte Mesochorus marginatus THOMSON ) but differs from that taxon by its pale face and form of ovipositor sheath. If the position in the pectoralis -group would be accepted, it can be correctly identified in the key for this group ( SCHWENKE, 1999: 95–98). The taxon is further characterized by its long and continuously narrowed ovipositor sheath and the short and almost diamond-shaped area superomedia.

Figures

Fig. 2a-d: Holotype of Mesochorus amnicolaris SCHWENKE:a. face; b. mesosoma; c. metasoma; d. ovipositor sheath.