Les phaneres des pattes et des palpes chez deux especes de Tetranychidae. - Nomenclature et evolution au cours de l ontogenese. - One of the urgent and vital needs in understanding Acari is studying each family, in order to simplify and homogenize various terminologies. In this paper, we give the nomenclature and sorne properties of all setae on legs and palps of Tetranychidae. We study z species: Tetranychus neocaledonicus Andre and Petrobia harti (Ewing) . For each species, we examine each article of each leg during ontogenesis. Each seta is noted with precision and each is recognized stasis after stasis. It seems that T. neocaledonicus represents a classic model. Petrobia ha1 ti, because of an important neotrichy and an extreme elongation of the articles during ontogenesis, is more interesting: on the tarsus and tibia of leg I, especially in males, all larval, protonymphal and deutonymphal normal setae are reduced into reduced setae just behind new solenidions. This resarch is incomplete: only z genera have been studied; however each specialist will now to make an intensive and deep study of other genera. Therefore, coordination bet.veen all terminologies and cooperation between specialists will be profitable and useful for Acarology.