The Ants (Hymenoptera: Formicidae) of Bol’shaya Svetlovodnaya (Late Eocene of Sikhote-Alin, Russian Far East) Author Dlussky, G. M. Author Rasnitsyn, A. P. Author Perfilieva, K. S. text Caucasian Entomological Bulletin 2015 11 1 131 152 journal article Genus Lasius Fabricius, 1804 Type species Formica nigra Linnaeus, 1758 ; by subsequent designation by Bingham, 1903 : 338. Diagnosis (for fossil imprints). Waist consisting of 1segment (petiole) with scale; gaster without constriction between 1st and 2nd gastral (abdominal III and IV) segments. Head with rounded occipital angles. Anterior margin of clypeus rounded. Eyes situated above middle of head sides, gena of gynes and workers much longer than maximum eye diameter. Mandibles of gynes and workers triangular, dentate. Antennae 12-segmented in gynes and workers and 13-segmented in males; scape protruding beyond posterior margin of head. Second to fifth joints of funiculus of gynes and workers 1–1.4times as long as wide (except in the subgenus Dendrolasius Fabricius, 1804). Antennal insertion near posterior margin of clypeus. Hind coxae broadly separated. Forewing with closed cells 1+2r, 3r and usually mcu, free branches 5RS and 4M leaving cell 1+2r from common knot. 4M strongly curved basally. Section2RS+M (under1+2r cell) straight or weakly convex. Icu>1.45. Gynes 1.5–2.2times as large as males (except in the subgenus Austrolasius Fabricius, 1804). Species included. Acording Bolton’s online catalogue [ Bolton, 2015 ] a total of 114 extant valid species and subspecies of Lasius distributed in the Palearctic and Nearctic are known to date. Bolton’s catalogue also includes a checklist of 25extinct species and subspecies distributed in Eocene, Oligocene and Miocene. Fossil taxa badly need in revision, for some of them are possibly deserve synonymization, and some other belong elsewhere. Notes. There are 11fossils in the collection studied with the wing venation and general appearance characteristic of the genus. Judging from the size, they represent two species. Unfortunately, the preservation state is not sufficient to provide their formal description, so we present only their registration numbers and measurements available.