The genus Manophylax (Trichoptera: Apataniidae) currently contains three species in the Nearctic region and three species in Japan. A new species of Manophylax is described and figured from Alaska, bringing to seven the number of known species in the genus.  Keys for adult males, larvae, and pupae of the four North American species of Manophylax are provided.  A phylogeny of the seven world species and their historical biogeography is given along with a consideration of the phylogeny and classification of the genus in Apataniidae.