Bumblebee (Hymenoptera: Apidae, Bombini) fauna of the forest-steppe and steppe zones of the West Siberian Plain
32 species of <i>Bombus </i>and 7 species of <i>Psithyrus </i>are recorded in the forest-steppe and steppe zones of the West Siberian Plain. The distribution of some bumblebee species in West Siberia with confusing or mistaken reference data, has been re-examined. The westernmost localities for <i>B. pseudobaicalensis </i>Vogt, 1911, and easternmost for <i>B. sylvarum </i>(Linnaeus, 1761) are presented. It is shown that bumblebee diversity in West Siberia distinctly decreases southward.