A new species of Metopiinae (Hymenoptera, Ichneumonidae) parasitizing lepidopteran larvae in China

Abstract A new species of Metopiinae, Trieces etuokensis Sheng, sp. n., is described and illustrated. Specimens were reared from two species of Lepidoptera: Bazaria turensis (Ragonot, 1887) (Pyralidae) from Balong, Dulan, Qinghai Province, and an unidentified psychid (Psychidae) from Mukainor, Etuoke, Inner Mongolia Autonomous Region, China. The new species is characterized by a yellow face and clypeus, fore and middle femora and hind tibia mainly black, antennae slightly longer than head and mesosoma combined, with 17 flagellomeres, occipital carina entirely absent, and the hind femur being compressed, 2.5 times as its long as maximum width.


Introduction
Trieces Townes, 1946 (Hymenoptera, Ichneumonidae, Metopiinae) comprises 68 species (Tolkanitz 2010, Yu et al. 2012, of which 13 are from the Eastern Palaearctic Region (Tolkanitz 2010). No species of Trieces have been reported from China to date. The genus is characterized mainly by areolet absent, mesopleural suture indistinct or absent, lateral carina of first tergite weak or obsolescent, second tergite with complete median and sublateral longitudinal carinae, basal portion of sublateral longitudinal and median carinae of third tergite present, and epipleura of third to fifth tergites almost absent (Townes 1971, Gauld et al. 2002, Tolkanitz 1987, 2010.

Materials and methods
Mature larvae of the host, Bazaria turensis (Ragonot, 1887) were collected on 28 August 2013 in a forest from where there had been an outbreak lasting at least three years, and brought to the laboratory. The forest is a shrubbery (Fig. 1) composed of Nitraria tangutorum Bobrov, Lycium chinense Miller var. potaninii (Pojarkova) A.M. Lu and Kalidium foliatum (Pallas) Moquin-Tandon, located in Dulan County, 36°09.65'N; 97°27.42'E, Qinghai Province. Mature larvae were maintained in a nylon cage at room temperature, and after pupating were stored individually in glass tubes (60 × 6 mm) with a piece of filter paper dipped in distilled water to maintain moisture and plugged tightly with absorbent cotton. After the emergence of moths and parasitoids was complete, remaining pupae were dissected to record their condition (i.e. status of moths, and parasitism).
Mature larvae of the psychid moth were collected in 16 September 2014 from a scrub where there had been an outbreak lasting at least fourth years, and brought to the laboratory. The scrub (Fig. 2)  Images were taken using a Leica M205A Stereomicroscope with LAS Montage MultiFocus. Morphological terminology is mostly based on Gauld (1991).
Type specimens are deposited in the Insect Museum, General Station of Forest Pest Management (GSFPM), State Forestry Administration, People's Republic of China.

Trieces Townes, 1946
Trieces Townes, 1946 Diagnosis. Malar space approximately as long as basal width of mandible. Ocular-ocellar line as long as diameter of posterior ocellus. Antenna slightly longer than head and mesosoma combined, with 17 flagellomeres. Occipital carina entirely absent. Metapleuron shiny, impunctate, lower posterior portion with distinct wrinkles. Hind femur compressed, 2.5× as long as maximum width. Face and clypeus yellow. Fore and middle femora and hind tibia mainly black.
Description. Female. Body length approximately 2.8 mm. Fore wing length approximately 2.2 mm.
Head. Inner margins of eyes distinctly convergent downwards. Face (Fig. 4) with dense fine punctures, distance between punctures 0.2-0.5× diameter of puncture. Clypeus with denser punctures than that of face, distance between punctures approximately 0.2× diameter of puncture, apical portion slightly concave; apical margin almost truncate. Mandible small, weakly narrowed toward apex; upper tooth distinctly longer than lower tooth. Malar area flat, with fine punctures. Malar space approximately as long as basal width of mandible. Gena in dorsal view approximately as long as width of eye, almost smooth, with sparse, indistinct fine punctures, scarcely convergent posteriorly. Vertex (Fig. 5) and frons almost shiny, with indistinct fine punctures. Postocellar line 1.2× as long as ocular-ocellar line. Ocular-ocellar line approximately as long as diameter of posterior ocellus. Upper portion of frons slightly convex, lower portion slightly concave. Antenna (Fig. 6) slightly longer than head and mesosoma combined, with 17 flagellomeres; each flagellomere longer than wide. First flagellomere 2.2× as long as maximum width, 1.1× as long as third flagellomere. Occipital carina absent. Remarks. This new species is similar to T. pumicatus Tolkanitz, 2010 and can be distinguished from the latter by the following combination of characters: antenna slightly longer than head and mesosoma combined, with 17 flagellomeres (female); fore wing with vein 1cu-a distinctly distal of 1-M, distance between them 0.4× length of 1cu-a; hind femur compressed, 2.5× as long as maximum width; lateral longitudinal carinae of tergite 3 distinct on anterior 0.3; fore and middle femora, hind tibia mainly black; basal ventral profile of antennae red brown, basal dorsal profile darkish brown; apical portion brownish black. The same characters for Trieces pumicatus Tolkanitz are as follows: antenna not longer than head and mesosoma combined, with 20 flagellomeres (female); fore wing with vein 1cu-a slightly distal of 1-M, nearly interstitial; length of hind femur 2.2× its width; lateral longitudinal carinae of tergite 3 vanishing behind its middle; fore and mid legs, hind tibia reddish yellow, fore and mid femora slightly darkened on outer side; antenna reddish yellow.