Archaeochrysa Adams, 1967: 217, 219, 220, 229; Schlüter 1984: 7; Yang & Hong 1990: 20; Willmann & Brooks 1991: 126, 128, 130, 131; Adams & Penny 1992a: 39; Adams & Penny 1992b: 221; Carpenter 1992: 347; Willmann 1993: 242, 244; Peñalver et al. 1995: 486; Ren & Guo 1996: 471; Nel et al. 2005: 67; Makarkin & Archibald 2013: 134, 141, 142, 144; Archibald et al. 2014: 191; Makarkin 2014: 4; Archibald & Makarkin 2015: 359, 362, 364; Archibald & Makarkin 2017: 400; Makarkin et al. 2018: 534; Tauber 2019a: 14, 15; Tauber 2019b: 36.
Type species. Palaeochrysa creedei Carpenter, 1935, by original designation.
Emended diagnosis. May be distinguished from other genera of Nothochrysinae by a combination of the following. Forewing: (1) M forked far distad origin of RP [other genera: proximad to slightly distad]; (2) one crossvein between RA, RP proximad 1r-m present [other genera: absent]; (3) im relatively narrow, elongate [Cimbrochrysa Schlüter, 1982, Danochrysa Wilmann, 1993, Asiachrysa Makarkin, 2014, Okanaganochrysa Makarkin & Archibald, 2013, Leptochrysa: broadly pentagonal; Hypochrysa, Asthenochrysa: broadly triangular]; (4) two gradate series in radial space [Okanaganochrysa, Triplochrysa: three; Dictyochrysa, Adamsochrysa Makarkin & Archibald, 2013: four or more]. Hind wing: (5) MA not fused with RP (connecting by crossvein 1r-m) [other genera: fused (except Leptochrysa, Stephenbrooksia Wilmann, 1993)]; (6) MP not fused with CuA (connecting by crossvein 2m-cu) [probably all other genera: fused or contacting]
Species included. Six species: Archaeochrysa profracta Makarkin & Archibald, 2013 (early Eocene of McAbee, British Columbia, Canada); A. sanikwa Archibald & Makarkin, 2015 (early Eocene of Driftwood Canyon, British Columbia, Canada); A. paranervis Adams, 1967, A. fracta (Cockerell, 1914), A. cockerelli sp. nov. (all from late Eocene of Florissant, Colorado, USA); A. creedei (Carpenter, 1935) (Oligocene of Creede, Colorado, USA).
Occurrence. Eocene (Ypresian to Priabonian) and Oligocene of North America.