Abstract The North American species of Lasionycta Aurivillius are revised to include 43 species and 13 subspecies using traditional methods and mitochondrial cytochrome oxidase subunit 1 (CO1) DNA sequence (barcode) analysis. Seven species-groups are recognized, and one group is further divided into seven sub-groups. Seventeen species and six subspecies of Lasionycta are described: L. anthracina Crabo & Lafontaine, L. benjamini medaminosa Crabo & Lafontaine, L. brunnea Crabo & Lafontaine, L. caesia Crabo & Lafontaine, L. carolynae Crabo, L. coracina Crabo & Lafontaine, L. fergusoni Crabo & Lafontaine, L. frigida Crabo & Lafontaine, L. gelida Crabo & Lafontaine, L. haida Crabo & Lafontaine, L. illima Crabo & Lafontaine, L. mono Crabo & Lafontaine, L. uniformis fusca Crabo & Lafontaine, L. uniformis handfieldi Crabo & Lafontaine, L. uniformis multicolor Crabo & Lafontaine, L. uniformis shasta Crabo & Lafontaine, L. perplexella Crabo & Lafontaine, L. pulverea Crabo & Lafontaine, L. sasquatch Crabo & Lafontaine, L. sierra Crabo & Lafontaine, L. silacea Crabo & Lafontaine, L. subalpina Crabo & Lafontaine, and L. subfuscula livida Crabo & Lafontaine. Lasionycta coloradensis (Richards), L. dolosaL. flanda (Barnes & Benjamin), (Smith), L. poca (Barnes & Benjamin), and L. subfumosa (Gibson) are elevated to species. The following new synonyms are recognized: Scotogramma albinuda Smith (= Lasiestra phoca Möschler), Lasiestra klotsi Richards (= Scotogramma discolor Smith), Scotogramma infuscata Smith (= Mamestra promulsa Morrison), Lasionycta alberta Barnes & Benjamin and Anytus marloffi Smith (= Scotogramma perplexa Smith), Scotogramma sedilis Smith (= Scotogramma subfuscula Grote), Mamestra rainieri Smith (= Mamestra mutilata Smith), Anarta zemblica Hampson (= Anarta staudingeri Aurivillius), and Anarta etacta Smith (= Mamestra arietis Grote). The Eurasian species are reviewed resulting in the following changes: Lasionhada proxima (Hübner), comb. rev., Eriopygodes imbecilla (Fabricius), comb. rev., Lasionycta dovrensis (Wocke), stat. rev. and L. fumida (Graeser), stat. rev. The genus Psammopolia Crabo & Lafontaine (type species: Polia wyatti Barnes & Benjamin) is described, resulting in the following new combinations: Psammopolia arietis (Grote), comb. n., Psammopolia insolens (Grote), comb. n., Psammopolia ochracea (Smith), comb. n., Psammopolia sala (Troubridge & Mustelin), comb. n., and Psammopolia wyatti (Barnes & Benjamin), comb. n. Two new species of the related genus Tricholita Grote are described: T. ferrisi Crabo & Lafontaine from southwestern Arizona and T. knudsoni Crabo & Lafontaine from western Texas. Adults and genitalia of all North American Lasionycta and Psammopolia species and the new Tricholita are illustrated. Keys to species-groups and species are presented. DNA barcodes of 39 of the 43 species were sequenced and are presented as neighbor-joining phylograms. The barcodes support the taxonomy at genus and species-group level, but not consistently at the sub-group level. At the species-level, performance of DNA barcodes was variable; 17 of the 39 barcoded species exhibited haplotype variation discordant with morphology, phenotype and distribution. A high frequency (43.6 %) of haplotypes were either shared among more than one species (representing eight species), or were closely similar and nested within haplotypic variation of other species (nine species).