Two subgenera (nominotypical subgenus Orthopsylloides and Mirzapsylla, new subgenus) are established within the flea genus Orthopsylloides Rothschild and Jordan, 1922. Within subgenus Orthopsylloides, four new species are described: Orthopsylloides (Orthopsylloides) mardoni, O. (O.) maricaballa, O. (O.) penguinata, and O. (O.) uncinata. An additional four new species are described in the new subgenus Mirzapsylla: Orthopsylloides (Mirzapsylla) rawlinsi, O. (M.). repanda, O. (M.) truncata, and O. (M.) whitingi. Females of O. (M.) mardoni and O. (M.) rawlinsi remain unknown. Orthopsylloides (O.) orthodactylus owiensis Holland, 1969, and Orthopsylloides (O.) abacetus baiyerensis George and Beaucournu, 1995, are each synonymized with their nominate taxa. Nine additional new species of the genus Parastivalius Holland, 1969, are described: P. avicularius, P. bidenticulatus, P. chelaformis, P. longipalpus, P. novaebritainiae, P. papillatus, P. phocaceus, P. spinatus, and P. tridenticulatus. Host associations are discussed and a table of host/parasite relationships is provided. An illustrated key to the valid species of Nestivalius Traub, 1980, Orthopsylloides, and Parastivalius is included. With the addition of 17 new species and new synonymy of two subspecies, there is a total of 93 species within the superfamily Pygiopsylloidea in Papua Province (Indonesia), Papua New Guinea (PNG, including Bismarck Archipelago), and the Solomon Islands. An additional eight species belonging to three other flea families [Ischnopsyllidae (3), Pulicidae (3), and Leptopsyllidae (2)] bring the total number of valid flea taxa in the region to 101 species (including subspecies).