EN
Hymenolepis diminuta tapeworms of the WMS "strain", obtained at 1 month and at 2.5 months after the administration to rats of cysticercoids, showed a right-hand side position of the genital pores (PGP). In the 5th month of infection strobilas of variable PGP were also found to appear. These two types of strobilas (of right-hand side and variable PGP) appeared till the end of the observation period in the 23rd month after the infection of rats. It was established that the variability of PGP depends on the duration of the infection and not on the age of the final host. Apart from typical proglottids containing 1 testis on the poral side and 2 testes on the aporal side (lp2a) there were also proglottids of the following numbers and placement of testes (NDT): 0p0a, 0pla, 0p2a, 0p3a, 0p4a, 0p5a, 1p0a, 1p1a, 1p3a, 1p4a, 1p5a, 2p0a, 2p1a, 2p2a, 2p3a, 2p4a, 3p0a and 3p1a. Correlation was established between the frequency of occurrence of PGP changes and the number of proglottids with the following NDT: 1p2a, 2p1a, 3p0a, 3p1a and all deviations from 1p2a.