Material examined (2 f). – Female holotype and one female paratype: Australia, central New South Wales, Round Hill, near Lake Cargillego, taken at night at lamp-light, 11 January 1981, leg. GY. HANGAY et A. VOJNITS. – Holotype is deposited in the National Insect Collection, Canberra and of fore wing of female paratype the paratype in the Hungarian Natural History Museum (Department of Zoology) Budapest, Hym. Typ. No. 10704. – The holotype and the paratype are in good condition: glued on a pointed card by their mesosternum; right antenna of the paratype is damaged (having only 15 antennomeres).

Etymology. – The species name “rutilus ” refers to its russet body colour.

Description of the female holotype. – Body 5.5 mm, fore wing 4 mm long. Antenna with 21 antennomeres as long as head, mesosoma and first tergite combined. First flagellomere 2.3 times, penultimate flagellomere 2.8 times as long as broad, flagellum attenuating distally. Antennal sockets 2.4 times as far from each other as one socket from eye. – Head in dorsal view (Fig. 37) transverse, twice as broad as long, eye twice as long as temple, temple constricted, occiput excavated. OOL 2.4 times longer than POL, ocelli of average size. Eye in lateral view 1.7 times as high as wide, temple 0.76 times as wide as eye; temporal carina curved (i.e. not angular) towards occipital as well as towards hypostomal carinae (Fig. 38). Maxillary palp about one-third shorter than height of head. Malar space one-third longer than basal width of mandible. Head coriaceous, temple polished; face rugulose laterally, medially uneven.

Mesosoma in lateral view twice as long as high. Precoxal suture finely crenulate, mesopleuron polished. Mesoscutum granulose, postero-medially longitudinally striolate; scutellum finely granulose. Propodeum densely rugulose. – Fore femur 2.2 times (Fig. 39), hind femur 3.3 times (Fig. 40) as long as broad medially and proximally, respectively. Tarsus of fore leg (Fig. 41) and claw of hind leg as in Fig. 42.

Fore wing: Pterostigma 3.3 times as long as wide issuing r distally from its middle, r a bit longer than width of pterostigma, submarginal cell short, 3–SR one-third (or 1.3 times) longer than 2–SR, r 0.77 times as long as 2–SR, SR1 weakly arched and 1.6 times as long as 3–SR (Fig. 43). First discal cell less elongate, 1–SR–M 1.7 times as long as 1–M, 1–M 1.4 times as long as m–cu (Fig. 44).

First tergite (Fig. 45) strongly broadening posteriorly, its length equal to its hind width, longitudinally striate, interstriation uneven and shiny, laterotergite just visible in dorsal view (see arrows in Fig. 45). Second tergite long trapeziform, 1.2 times wider behind than long medially, basally with fine striation, otherwise together with further tergites polished. Suture between tergites 2–3 indistinct. Oviositor sheath as long as hind tarsomere 1 and half of tarsomere 2 combined.

Ground colour of body rusty. Antenna darkening rusty to brown. Palpi pale yellow. Parastigma yellow. Propodeum and first tergite laterally blackish. Fore leg brownish yellow, middle and hind legs rusty, coxae and trochanters whitish. Wings subhyaline, pterostigma brown with yellow basal spot, veins brownish.

Description of the female paratype. – Similar to the female holotype. Body 5 mm long. Scutellum similarly coriaceous to mesoscutum. Fore femur 2.35 times as long as broad medially. 3–SR 1.38 times as long as 2–SR. First discal cell slightly less long, 1–SR–M somewhat refracted medially and 1.6 times as long as (Fig. 46). Fore half of second tergite finely striate.

Male and host unknown.

Distribution: Australia (New South Wales).

The new species, Mesocentrus rutilus, is nearest to M. crassipes SZÉPLIGETI, the distinction of the two species is presented in the key at couplets 4(5)–5(4).