Five species of oribatid mites were cultured on the fungi Penicillium martensii or Aspergillus flavus in Petri dishes and small glass cells. Data are presented on their !ife-cycles. The duration of the lifecycle varied considerably, and, in the case of species producing males, the duration of the male life-cycle was shorter than that of the female. Palaeacants kamenskii was seen to reproduce parthenogenetically. Belba meridionalis was cultured in glass cells on rz different species of fungi. As assessed by the population of all stages in the cells after 104 days, the most favourable diet was Trichodenna sp., and the least favourable Penicilliwn viridicatwn and Nhtco1 ramannianus. Data are also given on spermatophore production, and the structure of the spermatophore is described for a number of species