New Darwin wasps (Hymenoptera, Ichneumonidae, Tersilochinae, Tryphoninae) from the Eastern Palaearctic region

In this study, we describe two remarkable species, Ctenochira arkadyi Kasparyan, sp. nov. (Tryphoninae) from southern Siberia (Russia), and Probles arkadyi Khalaim, sp. nov. (Tersilochinae) from Japan. These two species are named in honour of our colleague and friend, an expert in Aculeata (Hymenoptera), Russian entomologist, Prof. Arkady Lelej, in honour of his 75th birthday. The recently described European species, Ctenochira magnusi Haraldseide, 2018, is discovered from the Russian Far East; the male of C. magnusi is recorded and described for the first time.


Introduction
In spite of the extensive study of Darwin wasps (the name suggested for the Ichneumonidae by Klopfstein et al. 2019) in the Eastern Palaearctic region during the past decades, fauna of this region remains understudied and comprises many undescribed taxa.
Palaearctic species of the large tryphonine genus Ctenochira Förster, 1855 (Tryphoninae) were revised by the first author (Kasparyan 1973) and several new taxa in this genus were described in a series of subsequent publications (Kasparyan and Tolkanitz 1999;Kasparyan and Khalaim 2007;Kasparyan 2013aKasparyan , 2013b. At present, Ctenochira comprises about 100 species worldwide (Yu et al. 2016), of which 70 species occur in the Palaearctic region (Kasparyan 2019).
Probles Förster, 1869 is a large almost worldwide genus of Tersilochinae with 74 described species, of which over 50 species occur in the Palaearctic region. The European fauna of the genus was revised by Horstmann (1971Horstmann ( , 1981, and in 21 st century new species were described in the Eastern Palaearctic region from China (Khalaim and Sheng 2009), South Korea (Khalaim et al. 2013;Balueva et al. 2014;Khalaim et al. 2017), Russian Far East (Khalaim 2014;Khalaim and Tereshkin 2019), and in the Oriental region from Vietnam (Khalaim 2011(Khalaim , 2018(Khalaim , 2019. However, many Eastern Palaearctic and Oriental species of Probles remain undescribed.
The aims of this study are to describe new species of Tersilochinae and Tryphoninae from the Eastern Palaearctic region and provide new faunistic records.

Material and methods
The specimens examined in this study were borrowed from or deposited in the following collections: the Matsuyama University, Ehime Pref., Shikoku, Japan (EUM), and the Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia (ZISP).
Morphological terms predominantly follow Townes (1969). Layer photographs were taken in ZISP, with an Olympus OM-D digital camera attached to an Olympus SZX10 stereomicroscope, and partially focused images were combined using Helicon Focus Pro (v. 7.6.6) software.
Description. Female. Body length 3.2 mm. Fore wing length 2.2 mm. Head with gena distinctly and roundly constricted posterior to eyes (Fig. 5); gena in dorsal view 0.45 times as long as eye width. Clypeus unusually small, 2.1 times as broad as long and 0.6 times as broad as face (shortest distance between eye margins), smooth, with very fine and sparse punctures in upper half, separated from face by sharp furrow (Fig. 3). Mandible strongly constricted in basal 0.7; width of mandible at level of teeth about 0.4 times width at base; lower tooth almost 1.5 times longer than the upper (Fig. 4). Malar space about 1.1 times as long as basal mandibular width. Flagellum with 16-17 flagellomeres, filiform (Fig. 2); second flagellomere almost twice, flagellomeres 3-5 about 1.8 times, and subapical flagellomeres 1.2 times as long as broad; flagellomeres 4 to 6 (or more) bearing very small subapical finger-shaped structures on outer surface (these structures hardly discernible with a light microscope). Face with median swelling. Face, frons and vertex finely granulate, impunctate, dull. Gena shallowly granulate, impunctate, weakly shining. Occipital carina complete, evenly convex mediodorsally. Hypostomal carina absent (at least in lower part).
First tergite about 3.4 times as long as posteriorly broad, more or less trapeziform in central cross-section; lateral sides of petiole distinctly longitudinally striate before glymma ( Fig. 10), petiole dorsally and postpetiole smooth; glymma deep, round, situated at posterior 0.55 of tergite and joining by thin and sharp furrow with ventral part of postpetiole (Fig. 10); in dorsal view, petiole with lateral margins subparallel, postpetiole distinctly widened anteriorly and almost twice broader than petiole (Fig. 9); upper margin of first tergite, in lateral view, nearly straight in anterior 0.7 and distinctly arcuate in posterior 0.3 (Fig. 10). Second tergite 1.5 times as long as anteriorly broad (Fig. 9). Thyridial depression deep and long, 2.5-3.0 times as long as broad, with posterior end rounded (Fig. 9). Ovipositor slender, weakly upcurved, with weak dorsal subapical depression (Fig. 11); sheath twice as long as first tergite (Fig. 1).
Male. Unknown. Etymology. The species is named in honour of the Russian entomologist, an expert in Mutillidae, Prof. Arkady S. Lelej (Vladivostok, Russia).

Subfamily Tryphoninae
Genus Ctenochira Förster, 1855 Remarks. Ctenochira is the largest genus of the tribe Tryphonini occurring in the Holarctic and Oriental regions, comprising about 100 species (Yu et al. 2016); the genus is best represented in the boreal and subarctic zones of the Holarctic region. The Nearctic fauna of the genus was revised by Townes and Townes (1949), and Palaearctic species were revised by Kasparyan (Kasparyan 1973(Kasparyan , 2013a. All species of Ctenochira are koinobiont ectoparasitoids of sawfly larvae of the family Tenthredinidae (Hymenoptera: Symphyta); the parasitoid female usually oviposits on exposed, living openly, larvae of the host. Comparison. Ctenochira arkadyi sp. nov. belongs to the C. flavicauda group of species characterized by the presence of the areolet in the fore wing and shortly pectinate tarsal claws. It differs from other species of this group in having metasomal tergites 2-4 distinctly, densely and uniformly punctate, and the propodeum with costulae. Ctenochira arkadyi sp. nov. is similar to the recently described C. magnusi Haraldseide, 2018, but differs from this species (as well as from most other congeners) by the features listed in Table 1.

Ctenochira arkadyi
Description. Female. Fore wing length 6.0 mm. Antenna with 29 flagellomeres; first flagellomere 4.0 times and second flagellomere 2.5 times as long as broad; combined length of flagellomeres 1 and 2 about 0.9 maximum eye diameter. Apical flagellomeres thin, about 0.6 times as wide as ba- only tergite 2 red tergites 2 and 3 (sometimes also 4) red Hind femur red, with small dark dorsoapical marking (Fig. 15) gradually darkening from reddish basally to blackish in 0.3-0.6 ( Fig. 19) sal flagellomeres. Sensillae starting on flagellomere 4 and continuing on subsequent flagellomeres. Head (Figs 13, 14) shining, not narrowed behind eyes, temples slightly convex. Face centrally convex and coarsely punctate. Clypeus weakly and evenly convex, polished, finely and sparsely punctate; clypeal foveae small, without setae. Frons with rather dense, even and moderately fine punctures. Temples with fine and sparse punctures. Margins of antennal sockets on frons not raised. Malar space about half as long as basal mandibular width. Oral carina slightly higher than occipital carina, and 0.6 times as long as basal mandibular width. Thorax smooth, with even, distinct, moderately large and dense punctures. Pronotum with rugosity on transverse impression and lateral lower corner. Mesoscutum without notaulus. Scutellum with lateral carinae on its anterior 0.4. Mesopleuron in upper half and posteriorly smooth, shining, with moderately large punctures which are separated by about 1.5 diameters of puncture (Fig. 15); speculum large and polished. Metapleuron with punctures denser (distance between punctures about 0.5-1.0 diameter of puncture); lower margin of metapleuron with deep impression covered with rugae. Propodeum with superficial rugosity, impunctate except for irregular punctures on smooth background on first lateral areas; costulae present, extending from hind part of areola; areola confluent with basal area, its lateral sides parallel. Apical area 0.55 times as high as length of propodeum (measured at midline), with median longitudinal carina distinct.
Metasomal tergites smooth, with dense and moderately large punctures; punctures denser on tergites 1-4 (Fig. 17), somewhat finer and sparser on posterior margins of tergites, on posterior half of tergite 4, and on tergite 5 (subsequent tergites retracted under tergite 5, see Fig. 18). First tergite about 0.9 times as long as wide, its longitudinal median dorsal carinae strong and extending to superficial transverse depression in posterior 0.2 of tergite; interspace between dorsal carinae broad, entirely densely punctate from transverse depression to base; transverse depression with short longitudinal rugae. Second and third tergites strongly transverse, about 0.5 times as long as broad; both tergites with shallow transverse depression just behind middle. Hypopygium large, with large oval desclerotized area medially in basal 0.7 (this area somewhat paler than its light yellow apical and lateral periphery); hypopygium with rather dense, erected and moderately long setae which are shorter than diameters of hind tarsomeres and extending to hind margin of hypopygium (Fig. 18). Ovipositor sheath 2.5 times as long as its median width, with dorsoapical emargination in its apical 0.4 (Fig. 18). Coloration (Fig. 12). Antenna blackish brown, scape and pedicel light yellow ventrally and flagellomeres 1-3 brownish yellow ventrally. Head black; face, clypeus, lower 0.3 of frontal orbits, palpi, mandible (except for reddish brown teeth), malar space, lower parts of gena and postgena yellow (Fig. 13). Mesosoma black; lower margin of propleuron (above fore coxa), tegula and plates at base of fore wing yellow; lower part of mesopleuron with obscure reddish marking ventrally (Fig. 15). Legs predominantly yellowish red. Fore and mid legs with coxae and trochanters entirely light yellow, and femora, tibiae and tarsi reddish yellow. Hind leg with coxa, trochanters and femur red; femur slightly darkened dorsally at apical 0.1; tibia brownish yellow in basal 0.6 and dark brown in apical 0.4; spurs yellow; hind tarsus brown, tarsomeres 1-3 pale at extreme base. Pterostigma dark brown with proximal 0.25 whitish.
Male. Unknown. Etymology. We are happy to name this new species in honour of Prof. Arkady Lelej, after his 75 th birthday and in recognition of his enormous contribution to the taxonomy of Aculeata and his hard work organizing extensive insect studies in the Russian Far East.
Material examined. Holotype female (ZISP), Russia, Transbaikal Territory, railway station Karymskaya, ravine in right bank of Ingoda river, taiga (Pinus, Larix), 28.VI.1975, coll Remarks. This is the first record of C. magnusi from Russia. The male of this species is described here for the first time. Variation. A female from the Russian Far East possesses hind tarsal claws with teeth slightly denser and concentrated at the base of the claw (Fig. 20) than in material from Europe.
Description. Male. Fore wing length 4.7-6.0 mm. Antenna with 28-30 flagellomeres, about ten basal flagellomeres thicker than subsequent ones. Head smooth, shining. Face weakly convex in profile, distinctly and rather densely punctate. Frons with distinct moderately dense punctures. Vertex and temple finely and sparsely punctate. Clypeus convex in upper 0.3, flat in lower part, almost impunctate. Malar space and oral carina behind mandible about 0.5 times as long as basal mandibular width. Pronotum laterally with large polished area, with subparallel striation near collar and at lower corner. Epomia weak. Mesopleuron finely and sparsely punctate, with large polished speculum and almost impunctate below subtegular ridge and next to mesopleural fovea along mesepimeron. Mesoscutum with uniform small and dense punctures. Notaulus very weak or absent. Scutellum with sparse moderately large punctures and distinct lateral carina on its anterior 0.4-0.5. Tarsal claw of fore leg with 4 (or 5) small teeth in basal 0.8; claw of mid leg with 3 small teeth in basal half; claw of hind leg with 3 teeth in basal 0.4. Metasoma shining, impunctate, tergites 1 and 2 partly with longitudinal striation in posterior half, especially on postmedian transverse impressions; posterior half of tergite 3 and subsequent tergites smooth, with very fine punctures and pubescence.
Coloration. Antenna light brownish, scape and pedicel yellowish white ventrally, two or three basal flagellomeres brownish yellow ventrally. Head black; face, clypeus, malar space, palps, mandible (except for teeth) and part of gena from level of lower 0.3 of eye to mandible whitish. Mesosoma black; small spot in hind corner of pronotum whitish, tegula and plates at base of fore wing white. Fore and mid legs and hind coxa light reddish yellow, all trochanters yellow. Hind femur light brown, pale reddish in basal 0.2; hind tibia dull yellowish with apical 0.2 light brown. Metasomal tergites black, tergites 2 and 3 reddish, and tergite 4 in one specimen with small reddish marking at base. Sternites brown with yellow median longitudinal fold on sternites 1-5 (or 6).
Distribution. Norway, Germany, Russia (south of Far East).