Sur le genre Holoparasitus Oudemans et sur certains caracteres morphologiques de la famille Parasitidae Oudemans. On the basis of new morphological data, which have been taken into consideration in the systematics of Parasitina mites within the last years, the genus Holoparasitus Oudem. can bo divided into two subgenera: Holoparasitits s. str. and Heteroparasitits n. subg. In the subg. Holoparasitits three species groups, calcaratits, pollicipatus and caesits may be recognized. The author describes three new species: H. fortunatus n. sp., H. tuberculatus n. sp., H. mallorcae n. sp. H. hemisphaericus (Vitzthum, 1923) is synonymized with H. apenninorium (Berlese, 1905). The genus Ologamasiphis Athias, still considered by some authors as belonging to the G. Holoparasitus Oudem., is an independent phyletic lineage. The value of the morphological characters in the taxonomy of the g. Holoparasitus Oudem. as well as in the family Parasitidae is discussed and the diagnosis of the tribes Pergamasini and Paragamasini given.