Four species of the genusHarrisoniellaBedford, 1929 are recognised; 2 further species are placed in synonymy. These, together with their hosts, areH. ferox(Giebel, 1867) (=D. irrorataeKéler, 1957new synonymy;=H. chilensisCarriker, 1964new synonymy) onDiomedea melanophrys melanophrys, D. m. impavida, D. irrorata, D. cauta cauta, D. c. salvini, andD. bulleri;H. densa(Kellogg, 1896) onD. albatrusandD. immutabilis;H. hopkinsiEichler, 1952 onD. exulans exulans, D. e. chionoptera, D. epomophora epomophora, andD. e. sanfordi;H. copeiTimmermann, 1969 onD. nigripes.