Observations morphologiques sur Polyapis patavinus Berlese 1881 (acariens: uropodites). 1. Morphologic de l idiosoma au cours du developpement postembryonnaire. In the Massane forest (Pyrenees-Orientales, France), Polyaspis patavinus Berlese 1881 occursmainly in the sa~roxylic bio~opes. Sorne recent data compiled in the literature about the systematic status of the family Polyaspidae and the systematic composition of the genus are g1ven. The morphology of the ventral, dorsal and lateral surfaces is studied during the ontogenetic development. Special attention is given to several features of the cuticle, the female endogynium and the cuticular glands. Dimensional ratios of the chelicera are proposed in order to compare its stoutness with that of other uropodid taxa.