The results of crosses carried out between the strains originating from regions of Europe distant from each other, i.e. from Spain and Hungary as well as between them and the standard strain of P. pentaurelia from Pennsylvania, USA are presented. It seems that the studied strains are not genetically differentiated within P. pentaurelia and that the species is characterized by moderate inbreeding.
E. Przybos, Department of Experimental Zoology, Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Slawkowska 17, 31-016 Krakow, Poland