(Figs 2 A–E)
Type material. HOLOTYPE ♂: RUSSIA, Sakhalin, 20 km S Yuzhno-Sakhalinsk, Dachnoe, 25.VII. 1962, leg. Shamyshev. PARATYPES: 15 ♂, same data as holotype; 1 ♂, Sakhalin, 29 km SW Yuzhno-Sakhalinsk, Urozhayny, 13.VII. 1962, leg. Shamyshev; 3 ♂, Sakhalin, 38 km W Yuzhno-Sakhalinsk, Pyatireche, 28.VII. 1962, leg. Shamyshev. Types deposited in the Zoological Institute of the Russian Academy of Sciences.
Description. Male. Frons black with a greenish tint, brilliant, with gray pollinosity on top of face, width of face at middle twice width of postpedicel (1.1: 0.6). Proboscis black. Palpus black, with black hairs. Antenna black. Postpedicel triangular, about as long as wide, with yellow hairs. Arista black, inserted near apex of postpedicel. Ratio length to width of postpedicel to length of arista 0.5: 0.6: 3.1. Postocular bristles below white, proboscis with some black bristles. Mesonotum greenish-black, with gray pollinosity. Propleuron with 2 short, black hairs. More than 5 small additional setae between sr and anteriormost dc; 1 npl, 1 sa, 7–8 pairs of dc, which increase in length from front to back; ac arranged in 2 rows, well developed, posteriormost bristles longer than distance between rows; 1 pair of strong scutellars with 1 pair of short lateral bristles. Legs black, knees yellow. Fore coxa with black hairs. Fore femur in apical quarter with some long av hairs. Fore tibia without strong bristles, with short hairs. Fore tarsomere 1 with short ventral hairs. Fore leg length ratio (from tibia to tarsomere 5) 3.7: 1.7: 0.9: 0.7: 0.4: 0.7. Mid femur with long ad hairs, longer than width of femur. Mid tibia in basal third with 1 ad and 1 pd bristle, apically with 1 long bristle. Mid leg length ratio (from tibia to tarsomere 5) 4.1: 2.5: 1.1: 0.8: 0.5: 0.6. Hind femur with long black bristles, about as long as width of femur. Hind tibia and tarsomeres with black short hairs. Hind leg length ratio (from tibia to tarsomere 5) 5.7: 1.4: 2.1: 1.2: 0.5: 0.6. Wing transparent, with yellow veins. Basal section of CuA without swelling. R 4 + 5 and M 1 + 2 convergent. M 1 + 2 in apical part slightly curved. Ratio costal section between R 2 + 3 and R 4 + 5 and between R 4 + 5 and M 1 + 2 2.4: 0.4. Apical segment of M 1 + 2 longer than basal segment: 5.8: 7.4. Apical part of M 3 + 4 longer than crossvein dm–cu: 1.1: 2.4. Anal lobe small, anal angle obtuse. Calypter yellow with dark yellow hairs. Halter yellow. Abdomen black, with black hairs, and gray pollinosity. Hypopygium black, surstylus and cercus dark yellow. Epandrium (Fig. 2 A) oval, tapering in apical half, length greater than width. Surstylus (Fig. 2 E) narrow, curved, not divided into dorsal and ventral arms; length greater than width; with finger–like dorsoapical projection bearing 2 setae, with ventroapical conical process, and with 1 strong apical and 1 subapical seta. Hypandrium (Fig. 2 D) parallel–sided, with rounded apex. Cercus (Fig. 2 C) elongate-oval, with 2 strong, curved apical spines. Female. Unknown. Length (mm): body 1.8–1.9, wing 2.0– 2.1.
Etymology. The species is named after the collecting site Sakhalin.
Remarks. In the Palaearctic key (Negrobov & Stackelberg 1971 – 77), the new species runs to Medetera borealis Thuneberg, 1955, but can be distinguished by the following characters:
1 Ventral arm of surstylus with conical process ventroapically (Fig. 2 A); hypandrium with round apex (Fig. 2 D)....................................................................................... Medetera sakhalinensis sp. nov . - Ventral arm of surstylus without conical process ventroapically; hypandrium with ovate apex........... Medetera borealis