This paper presents a further step in a revision of the fossil family Orthophlebiidae. A new fossil subfamily, Gigaphlebiinae subfam. nov., and two new genera, Gigaphlebia gen. nov. and Longiphlebia gen. nov., are established within Orthophlebiidae. The new subfamily comprises species characterized by a large size, ninebranched (exceptionally eight-branched) radial sector in both wings, and medial sector with six branches in the fore- and five in the hindwing. Four species, Gigaphlebia grandis comb. nov., G. palmaris comb. nov., G. riccardii comb. nov., and Longiphlebia stigmosa comb. nov. were transferred from genus Orthophlebia and Mesopanorpa. The diagnoses of newly established taxa are presented, all transferred species are redescribed and refigured. The significance of orthophlebiid taxonomy in the phylogeny of the Panorpoidea is discussed.