General description: In the first version of the list of ants of the Lower Volga region (Grebennikov et al., 2002) for several locations in the Volgograd region I was mentioned Lasius platythorax Seifert, 1991. However, after a more thorough study of the material, I came to the conclusion that it is impossible to reliably separate these species by morphological features (at least specimens collected in the Lower Volga region). Thus, L. niger is given here in a wide conception, without separating the “sibling” species L. platythorax. In this conception, this species is one of the most common ants in the Lower Volga region in moderately humid habitats: grasslands, bushes, forests (usually in slightly more shaded and humid habitats than L. alienus sensu lato).