Microchelonus nomas Tobias, sp. n.

This species is closely related to a Mongolian species, M. ventosus Tobias, 1989; differing in longer 2nd radiomedial cell, smoothed sculpture on scutellum, and more lightly colored wings. As regards the male, the new species is similar to M. scabrosus (Szépligeti, 1896), differing in less coarse sculpture on metasoma, lightly colored wings, and shorter radial vein.

Female. Body length 3-3.6 mm. Head strongly roundly narrowed behind eyes, 1.1 times wider than mesonotum, nearly oval anteriorly, slightly less convex dorsally than ventrally, twice as wide as long, 1.2 times wider than high. Tempora 1.2 times shorter than, or as long as eye. Base of ocellar triangle as long as the distance from hind ocellus to eye or somewhat shorter (5 : 6). Space between hind ocelli equal to 0.5 ocellus diameter. Longitudinal eye diameter 1.6 times longer than transverse one, 3 times longer than gena height, as long as face width. Face 1.8-2 times as wide as high, 1.2-1.4 times as high as clypeus. Labial palpi slightly longer than face height. Antennae equal in length to head and mesosoma combined, weakly setiform, with depressed ventrally apical segments. 1st antennal segment 3 times longer than wide, two preapical segments as long as wide. mesosoma 1.3 times longer than high. Propodeum without transverse cylinder, with rather small, obtuse denticles. Radial cell twice as large as 2nd radiomedial one, with anterior margin 1.3-1.5 times shorter than pterostigma. Radial vein has an acute angle with longitudinal axis of pterostigma; 2nd segment of radial vein slightly longer than, or as long as 1 st segment, 3-4 times as short as 3rd one, 1.8-2 times shorter than 1st radiomedial vein; 3rd segment straight or weakly S-curved, or slightly curved outwards in apical half. Nervulus shifted from basal vein at a distance of entire or 0.7 nervulus length. Hind femur 3-3.5 times as long as wide. Inner spur on hind tibia as long as, or somewhat shorter than 0.4 length of 1st hind tarsal segment; 5th segment of hind tarsus a little longer than 3rd, significantly shorter than 2nd. metasoma nearly oval, slightly stronger narrowed basad than apicad, 1.5-1.6 times longer than wide, 2.1-2.6 times longer than high. Ovipositor thin, concealed or protruding by length of hind tarsus.

Body largely not coarsely rugous-punctured. Face finely sculptured, with abundant transverse rugae; tem-pora with thinner and more abundant rugae, but vertex behind ocelli with more smoothed rugae parallel to occipital cylinder. Mesonotum with smoothed sculp-ture, punctured, shining; with not coarse, irregular cellular sculpture in front of scutellum. Scutellum weakly punctured, shining. Propodeum densely, not coarsely rugous-punctured; in posterior half, with lon-gitudinal rugae divergent from abdominal opening. metasoma with abundant, sparse, sinuous and anastomosing longitudinal rugae extending to its posterior third.

Body coloration black. Apices of femora (to a greater extent in fore and middle femora than in hind femora), fore and middle tibiae, except apical third, brownish-yellow. Apical third of hind tibia brown, sometimes also apex of middle tibia brownish. Tarsi brown, with lightly colored 1st segment. Wing lightly colored, with pale-yellowish veins, brown pterostigma, light-brown veins surrounding radial and 2nd radiomedial cells.

Male. Body length 3.4 mm. Antennae setiform, as long as head, mesosoma, and 0.3 metasoma length combined; 21(rarely)-22-segmented. Preapical segment 1.3 times as long as wide, penultimate apical segment 1.5 times longer than wide. AAO parallel-sided, as wide as 0.5-0.65 metasoma width, about as high as 1/3 metasoma width; 3-4 times wider than high. Median process of AAO thin, parallel-sided, occasionally several times wider (in lateral view) than AAO height, or (rarely) massive, conical, as wide at base as about 0.5 AAO height.

Holotype: ♀, Turkmenia, Tashkepri na Murgabe, on flowers Descurainia sophia, 21.IV.1955 (Tobias). Paratypes: 9 ♀, 1 ♂, same locality, 3-15.V.1954 (Tobias); 1 ♀, Morgunovskii, near Kushka, elm and tamarisk, 11.VI.1968 (Tryapitsyn); 1 ♀, Karabil', 150 km ENE of Takhta-Bazar, 15.V.1990; 1 ♀, Indzherli-Cheshme, 40 km SSE of Puli-Khatum, Zul'fatar Mountain Range, Badkhyz, 5.VI.1990 (Volkovich); 1 ♀, Badhyz Nature Reserve, Akarchashme nature boundary, 2.V.1990 (Volkovich); 4 ♀ , 1 ♂ , same locality, 3.VI.1973 (Tanasiichuk). Tajikistan: 15 ♀ , 14 ♂ , 20 km NW of Kurgan-Tyube, Gandzhina, Aruktau Mountain Range, dry meadows, 31.V.1982; 2 ♀ , 3 ♂ , same locality, meadow, 30-31.1982 (Belokobyl'skii); 1 ♀, Dashti-Gurk (near Obikhingou River), southern slope of Peter I Mountain Range, 31.VIII.1985 (Budris). Uzbekistan: I ♂, 25 km SE of Sairoba, Kushtan-Tau Mountain Range, 9-10.VI.1984 (Volkovich).

Note. The shape diversity of median process of AAO in males is noteworthy. It is usually thin, parallel-sided, several times thinner than AAO height. However, in one male (Tashkepri, 3.V.1954) it is massive, conical, with cone base significantly longer than AAO half height. Two other males (Tashkepri, 4.V.1954; Gandzhina, 30-3 IN. 1982) hold an intermediate position. They are characterized by short and weakly conical apical process with base occupying much less than 0.5 AAO height. All these males were collected simultaneously with M. nomas males, possessing thin apical process, and M. nomas females, and were identical to them in all other characters. Thus, the series of M. nomas males show that, in spite of a rather strictly uniform AAO structure in Microchelonus species, single specimens may significantly deviate from the standard.