lmportance de I’étude des caractères morphologiques. de la biologie et de l’écologie a toutes les stases, pour établir la phylogenèse des acariens voisins des thrombidions. - The researches of these last years, about Thrombidiidae, permitted me to determine the place it occupies: - in the superfamily of Thrombidioidea; - in a group of superfamilies related to them: Erythraeoidea - Calyptostomaoidea - Johnstonianidae. Contrary to many authors, I think that to define a superfamily, a family, a genus, and then to establish the relationships between these different groups, we must have precise informations about the morphology of Acari, at every stasis: active (larvae, deutonymphs, adults) or inactive (prelarvae, protonymphs, tritonymphs). In this way, I could define the superfamily of Thrombidioidea, from author’s data, but especially by studying every stasis, thanks to breedings of several species of Thrombidions.