Hylaeus (Hylaeus) gracilicornis (Morawitz, 1867)
Prosopis gracilicornis Morawitz, 1867: 56, ♀, Ƌ (lectotype—Ƌ, designated by Dathe 1979: 165, “Terijoki” [Zelenogorsk, St. Petersburg, Russia], ZISP).
Hylaeus subtilis Förster, 1871: 1039, ♀ (type locality: Chur and Austria).
Hylaeus nigrolineatus Cockerell, 1924b: 577 –578, ♀, Ƌ (type locality: Primorskiy Terr., Russia).
Hylaeus gracilicornis: Dathe 1979: 165, 1986a: 289 .
Material examined. No additional specimens examined.
Distribution in Mongolia. Tuv Aimag (Fig. 4 b).
General distribution. Transpalaearctic, from France to Russian Far East.