The green lacewings (Neuroptera: Chrysopidae) of the late Eocene Florissant Formation (Colorado, USA) are revised. Thirteen species in six genera of Nothochrysinae are recognized, including four new species: Archaeochrysa cockerelli sp. nov., Cimbrochrysa americana sp. nov., C. major sp. nov., and Lithochrysa meyeri sp. nov. The validity of the genus Dyspetochrysa Adams, 1967 is tenuous; it might be a synonym of Archaeochrysa Adams, 1967. Lithochrysa Carpenter, 1935 and L. ferruginea (Cockerell, 1909) are considered a valid genus and species. A lectotype and paralectotype of Tribochrysa firmata Scudder, 1890 are designated. The genus Cimbrochrysa Schlter, 1982 is recorded from North America for the first time. Eocene chrysopid assemblages are briefly analyzed. The late Eocene Florissant assemblage is less diverse than those of early Eocene North America, and greatly differs from late Eocene European assemblages.