Mesochorus laricis, Hartig, 1838

Riedel, Ravenhorst Matthias, 2018, Contribution to the Palaearctic species of Mesochorus G (Hymenoptera, Ichneumonidae, Mesochorinae): 1. The M. fulvus-group, Linzer biologische Beiträge 50 (1), pp. 687-716 : 698-699

Mesochorus laricis HARTIG, 1838: 273 ( figs 33-38 )

Types missing ( HORSTMANN, 1986: 331), interpretation after the original description.

syn. nov. Mesochorus georgievi SCHWENKE, 2004: 85.

Ho l o t y p u s: (♀) Bulgaria, Stara Planina Mts., Gintsi vill., 1.200 mt; in Saperdapopulnea galls on Populus tremula, 17.3.2002, G. Georgiev (Munich), type studied.

Ta xonomica l re ma rk:Ihavestudiedthetypeof M. georgievi SCHWENKE. Head and mesosoma are completely reddish; the metasoma (brownish)-red with slightly darker apical tergites, the colour differences are small. Structure and colour are otherwise similar to M. laricis HARTIG, and Ifound no relevant differences between both species.

Description: ♀: Bodylength 6.5-8.0 mm. Flagellawith 35-48 segments; 1 st flagellomeres length c.7x width and 0.65x eye length; 2 nd flagellomeres length 3.8x width. Temples strongly narrowed behind eyes, length 0.55-0.6x eye width. Ocelli very large, OOD 0.6-0.8. Face punctate, with parallel sides or slightly convergent ventrally, width 0.95-1.0x length of clypeus+face and 0,82x eye length. MI 0.4. Malar spaces, ventral 0.4 of facial orbits and bases of mandibles finely striate. Mandibles with two equal teeth. Occipital carina complete medially. Genal carinae reach the hypostomal ones far from mandibular bases. Mesoscutum with fine, moderately dense punctures caudalmedially and with superficial punctures laterally; mesopleura with fine dense punctures dorsally and moderately dense punctures ventrally; metapleura with fine superficial punctures. Area basalis pointed or shortly sessile or stalked, rarely fused with area superomedia; area superomedia length 2.3-2.8x width and 1.5x length of area petiolaris, costulae basal to its middle; area petiolaris length 1.0-1.2x width. Hind femora length 5.1-5.4x height; hind metatarsi length 0.48x length of hind tibiae; hind claws slender, with 2-4 short basal teeth; distal fore tarsomeres slender, length c.3.0-3.2x width. Areolets pointed-sessile, oblique; 2 nd recurrent veins in or proximal to their middle; nervuli interstitial or slightly postfurcal (1x width); postnervuli intercepted in basal 0.25- 0.4; pterostigma length c.3.2-3.5x width. 1 st tergite length 2.9-3.5x width; postpetiolus smooth, length 1.6x width; 2 nd tergite length 1.2-1.5x width; thyridia large, transverse. Ovipositor sheaths completely pilose, length 6.2-7.1x height and 0.7-0.8x length of hind metatarsi.

Colour: Yellowish-red. Ocellar space sometimes more or less fuscous. Palps, mandibles except teeth, malar spaces, genae, sometimes ventral facial orbits, hind edges of pronotum, tegulae, wing bases, fore coxae and trochanters, sometimes also middle coxae yellowish. Hind tibiae sometimes slightly and indistinctly darkened at apex. Flagella more or less darkened distally. Pterostigmata pale ochreous, margins slightly darker. Ovipositor sheaths yellowish-red to reddish-brown.

♂: Flagella with 44 segments. Temples moderately and roundish narrowed behind eyes, length 0.6-0.75x eye width. OOD 0.8-0.9. Hind femora length 5.1-5.2x height. Mesopleura with very scattered punctures. Claspers very slender, apically blunt, not clubbed apically, length 20x width and 1.4x length of 2 nd hind tarsomeres.

Distribution: Bulgaria*, Czech Republic *, Georgia*, Germany, Norway*, Portugal*, Russia* (Karelia, Far East), Sweden*, Ukraine, United Kingdom*, Turkey.

Figures

Figs 33-38: Mesochorus laricis HARTIG ♀: (33) face, (34) propodeum, (35) head, (36) hind claw, (37) distal fore tarsomere, (38) ovipositor sheaths.