Les acariens du genre Riccardoella Berlese, 1923 parasites du poumon de mollusques gasteropodes pulmones terrestres - The genus Riccardoella Berlese, 1923 is revised. A new subgenus Riccardoella (Proriccardoella) (type species: Riccardoella oudemansi Thor, 1932) and two new species (Riccardoella (Proriccardoella) reaumuri and R. (P.) canadensis) are described. Host and parasites have followed a parallel-evolution. The most primitive species (subgenus Proriccardoella) being found in the most primitive molluscs, while the only species of the most evolved subgenus (the nominate subgenus) lives exclusively in the family Helicidae, considered as the most evolved among the land pulmonate gastropods