EN
Trombicula (L.) russica Oudemans 1902 (Acarina, Trombiculidae) was found to occur on Barbastella barbastellus (Schreber, 1774), captured in the region of Cracow during hiberbation. A certain parallelism in the incidence, temperature and light requirements is postulated for parasite and host. Four species of Trombiculidae are hitherto known to occur in Poland: one of them on bats, the remaining ones on small mammals living on the surface of the earth.