A new species of Schlettererius Ashmead from China, with a key to the species (Hymenoptera, Stephanidae)

A new species of Schlettererius Ashmead, 1900, S. chundanae sp. n., is described and illustrated from China. The other East Palaearctic species, S. determinatorius Madl, 1991, is redescribed and illustrated, the first host record is given and it is newly reported from China. A key to the species of the genus Schlettererius is included.


Introduction
The small genus Schlettererius Ashmead, 1900 (Hymenoptera: Stephanidae) is Holarctic and contains two described species. The species were revised by  and ; a male from Qinling Mts (Shaanxi, NW China) was provisionally identified as S. determinatorius Madl, 1991. This species was described from Korea and is only known from the female holotype. Some differences were ob-served, especially in the shape of the first tergite, but this could be the result of sexual dimorphism. Recently, one of us (JLT) collected a female in the Qinling Mts which obviously belongs to a new species. The earlier recorded male fits well with the new species and is considered to be conspecific. The biology is known only of the Nearctic S. cinctipes (Cresson, 1880) introduced into Tasmania from California for biological control of the introduced Sirex noctilio (Fabricius, 1793) (Hymenoptera: Siricidae;Taylor 1967;van Achterberg 2002). In this paper we report the East Palaearctic S. determinatoris Madl, 1991, from Chrysobothris succedana (Saunders) (Coleoptera: Buprestidae) in Larix sp. The new species is authored by the first two authors because they made the key and the formal description.

Material and methods
The studied specimens of the genus Schlettererius Ashmead belong to the collection of the Northwest University at Xi'an (NWUX), the Insect Museum, General Station of Forest Pest Management, Shenyang (GSFPM), the Parasitic Hymenoptera Collection of Zhejiang University at Hangzhou (ZJUH), the Naturalis Biodiversity Center at Leiden (RMNH) and the Hungarian Natural History Museum at Budapest (HNHM). The holotype of the new species is deposited in the collection of the College of Life Sciences, Northwest University at Xi'an.
The morphological terminology follows van Achterberg (2002). Observations and descriptions were made either under an Olympus SZ40 or an Olympus SZX11 stereomicroscope. Photographic images were made with an Olympus SZX12 motorized stereomicroscope combined with AnalySIS Extended Focal Imaging software and processed with Adobe Photoshop CS5, mostly to adjust the size and background. For the illumination a pair of 30W Megaman or 45W Jinsilai fluorescent lamps were used allowing easy observation of the sculpture of the specimens.  (Figs 4,28), but distinctly longer in S. chundanae (Fig. 15); second tergite sessile and smooth or slightly sculptured basally (Figs 4,28); posterior part of eighth metasomal tergite of female with distinct pygidial process (Figs 4,11,24); ovipositor sheath with wide ivory subapical band (Figs 10,11,22,24,34). Distribution. Nearctic, East Palaearctic and Australian (only Tasmania: introduced for biological control of introduced Siricidae).
Description. Holotype, female, length of body 12.4 mm, and of fore wing 9.2 mm.
Head. Antenna with 30 segments; frons coarsely obliquely rugose; three anterior coronal teeth large and acute, both posterior ones arcuate and lamelliform, with two small lobe-shaped carinae on each side in front of both posterior ocelli; behind level of coronal area having four curved, progressively smaller carinae followed by rugose area, rugae rather coarse, posteriorly narrowly reaching occipital carina and widely smooth laterally; temple non-angulate (Fig. 19), punctulate but largely smooth and shiny.
Mesosoma. Neck short and robust, transversely rugose, neck at much lower level than middle part of pronotum (Fig. 14); middle part of pronotum largely smooth and without a distinct carina posteriorly; propleuron with sparse large punctures, shiny and rather densely setose; mesonotum irregularly foveolate and area between smooth; notauli and median groove distinct; scutellum with some coarse punctures medially, foveolate laterally; axillae coarsely punctate; mesopleuron distinctly convex, convex part foveolate-punctate and covered with long whitish setae, medially convex part of metapleuron rugose and with long whitish setae, anteriorly crenulate and intermediate area smooth; propodeum densely irregularly rugose (Fig. 14).
Wings. Fore wing (Fig. 12): vein 1-M 3.4 times as long as vein 1-SR and curved; vein r ends slightly before level of apex of pterostigma; first subdiscal cell robust, 2.2 times as long as its maximum width, vein cu-a entirely pigmented.
Legs. Hind coxa robust, without tubercle dorsally and with strong and sparse rugae (Figs 18, 23); hind femur widened, sparsely punctate and with whitish setae ventrally and dark brown setae dorsally, area in between punctures smooth and shiny, ventrally with 3 large acute teeth (the anterior one much smaller than posterior ones) and several denticles in between (Fig. 16); hind tibia 1.3 times as long as hind femur, basal narrow part of hind tibia about 0.8 times as long as widened part, widened part ventrally distinctly obliquely carinate; hind basitarsus subparallel-sided, length of hind basitarsus 3.7 times as long as wide and 1.3 times as long as second tarsal segment.
Metasoma. First tergite 3.8 times as long as its maximum width (Fig. 15), 1.2 times as long as second tergite and 0.4 times as long as metasoma without first tergite, sub-cylindrical, distinctly transversely rugose, but medially irregularly rugose; base of second tergite finely sparsely rugose; remainder of tergites smooth and shiny; setose part of ovipositor sheath 1.7 times as long as body and 2.3 times as long as fore wing.
Colour. Black or blackish brown; tegula and palpi dark brown; scapus, pedicellus, malar space, mandible and patch near basal quarter of hind tibia partly brown; base of femora and of fore and middle tibiae and tarsi pale yellowish brown; remainder of fore and middle tibiae brown; veins and pterostigma largely dark brown, but base of pterostigma ivory; wing membrane slightly brownish but fore wing darkened near vein r and below parastigma; subapical ivory band of ovipositor sheath 1.9 times as long as apical blackish part (Fig. 22). Diagnosis. Posterior part of pronotum steeply elevated above its anterior part (Fig.  2); first metasomal tergite irregularly transversely rugose and about twice as long as its apical width (Fig. 4); second and third tergites yellowish brown (Fig. 4); subapical ivory band of ovipositor sheath of female about 3.5 times as long as apical blackish part (Fig. 10).
Description. Holotype, female, length of body 15.0 mm, and of fore wing 9.9 mm. Head. Antenna with 29 (right) or 30 (left) segments; frons (Fig. 32) coarsely transversely rugose anteriorly and remainder reticulate-rugose; three anterior coronal teeth large and rather acute, both posterior ones arcuate and lamelliform, with one small lobe-shaped carina on each side in front of both posterior ocelli; behind coronal area with five curved, progressively smaller carinae followed by rugae laterally and fine transverse carinae medially, remaining narrowly separated from occipital carina (Fig.  31); temple smooth and shiny except for some small punctures near eye, slightly widened behind eyes and rather rounded in dorsal view (Fig. 31).
Wings. Fore wing (Fig. 25): vein 1-M strongly curved and 2.4 times as long as vein 1-SR; vein r ends before level of apex of pterostigma; first subdiscal cell robust, 1.8 times as long as its maximum width.
Legs. Hind coxa stout, largely smooth, with some short striae and with a small (in lateral view acute) subapical dorsal tooth (Figs 29, 35); hind femur moderately slender, finely granulate and covered with sparse whitish setae, ventrally with 3 acute teeth (the basal one small) and some small teeth (denticles; Fig. 29); hind tibia 1.2 times as long as hind femur, basal narrow part of hind tibia 0.6 times as wide as widened part and with long ventral carina, widened part ventrally distinctly obliquely carinate (Fig. 29); length of hind basitarsus 3.6 times as long as wide. Metasoma. First tergite stout, sub-cylindrical, 2.1 times as long as its maximum width and about 2.4 times as long as its apical width (Fig. 28), irregularly transversely rugose, posteriorly less developed than anteriorly, laterally with whitish setae; second tergite slightly shorter than first tergite and smooth except some short crenulae medioanteriorly (Fig. 28); remainder of tergites smooth and shiny; ovipositor sheath 1.9 times as long as body and 2.9 times as long as fore wing.
Colour. Dark brown; head, scapus, pedicellus, fore leg (but tibia ivory basally), middle and hind tarsi and propleuron brown; malar space pale brown; wing membrane (but basally and area below base of pterostigma subhyaline) infuscate; all tibiae ivory basal band; subapical ivory band of ovipositor sheath of female about 1.7 times as long as apical blackish part (Fig. 34).
Male. Very similar to female, length of fore wing 10.0-10.2 mm, and of body 16-17 mm; both with 29 antennal segments and first tergite 2.4-2.5 times its apical width.