Halictus baleicus Cockerell 1937: 1 [Holotype: American Museum of Natural History, New York, USA; ♀, type locality = Ust- Balei (Balei, Chita Prov.), Russia].
Lasioglossum (Evylaeus) baleicum: Ebmer 1978a: 203; Ebmer 1995: 571; Ebmer 2006: 558, Figs 35–37 (♂); Murao et al. 2006: Table 1, Figs 3 B, 4C, 6E, 6F, 6I, 6L (♀♂); Murao & Tadauchi 2007: 217, Figs 36–38, 57D, 59D (♀♂), 244 (in key). Evylaeus (Fratevylaeus) baleicus baleicus: Pesenko 2007b: 83 (in key), 91 (in key), 103.
Diagnosis. This species is similar to L. caliginosum Murao et al. and L. vulsum (Vachal) from eastern Asia. Male of this species is separated these species by a combination of the following character states: clypeus generally black over entire surface; mesoscutellum with coarser rugulae (Murao & Tadauchi 2007, Fig. 36L); tibiae nearly black over entire surface; the gonostylus of genitalia rounded (Murao et al. 2006, Figs 6 E–F); and the ventral retrorse lobe of genitalia slender (Murao et al. 2006, Fig. 6 I). In contrast, in L. caliginosum, the clypeus generally black over entire surface, the mesoscutellum reticulate-punctate (Murao & Tadauchi 2007, Fig. 42L), the tibiae nearly black over entire surface, the gonostylus ovate (Murao et al. 2006, Figs 6A–B), and the ventral retrorse lobe broad (Murao et al. 2006, Fig. 6 G); in L. vulsum, clypeus with yellow spot on lower half, mesoscutellum punctate (Murao & Tadauchi 2007, Fig. 53L), tibiae with yellow spot basally and apically, gonotylus truncated on top (Murao et al. 2006, Figs 6 C–D), and ventral retrorse lobe slender (Murao et al. 2006, Fig. 6 H).
The differences of female among L. baleicum, L. caliginosum, and L. vulsum are shown by Murao et al. (2006). However, when examined additional specimens collected from Japan and the Korean Peninsula, their described differences are subtle as pointed by Pesenko (2007b). In conclusion, females cannot be clearly separated among three species.
Specimens examined. (n = 8) [South Korea] JJ: 5♂, Yonsil, Mt. Halla-san, 27. vii. 1990 (O. Tadauchi, ELKU); 3♂, Mt. Halla-san, alt. 1400–1500 m, 25. vii. 1990 (O. Tadauchi, ELKU).
Distribution. North Korea, South Korea, Russian Far East, China, Japan.
Flight period in South Korea. Male: July. According to Maeta & Sasaki (2014), the active phases of female in Japan were recognized the following three patterns: 1) spring solitary phase; 2) summer social phase; and 3) autumun mating phase.
Flower records in South Korea. Not recorded.
Comments. Lasioglossum baleicum is divided into two subspecies by Pesenko (2007b), the nominotypical subspecies ranging from the continent, and the ssp. insulicola from Sakhalin to Japan. Both subspecies are separated only by the ventral retrorse lobe of male genitalia broad or narrow. However, it is subtle to separate both subspecies only by this character. In the present paper, I do not consider to separate L. baleicum as two subspecies.