Abstract
Boreus (Mecoptera, Boreidae) species are reviewed. Two new Alaskan species are described (Boreus tananaensis Kane, sp. nov., Boreus timaryi Kane, sp. nov.), a previously synonymized species is resurrected (Boreus gracilis Carpenter, 1935, stat. res.), and morphological descriptions are provided for all five Alaskan species. A key to male and female Alaskan Boreus species is provided. An estimate of the mitochondrial gene tree, based on COI DNA barcodes, is used to infer relationships, and morphological species are tested using five molecular species delimitation methods. What is known about the subgeneric classification of Boreus, and how Alaskan species are classified, is discussed. A checklist of all 33 currently valid species of the family Boreidae is provided.