Dr. Kassai Tibor - Dr. Murai Éva szerk.: Parasitologia Hungarica 6. (Budapest, 1973)

tion was moat abundant in autumn 1970, at a minimum in 1969 and small in 1972.) 2) The differences according to sex and age are shown in Fig. 2. (It is based on 2912 - or 220 infested - specimens examined of the total number of 3097 specimens collected.) We did not find a relationship between age of specimens and degree of infestation with strobilocercosis in mobile voles. We have ascertained that the cysts have no discernble effect on the life of the hosts. The difference between sexes was negligible, but the degree of infestation in the varied specimens of different sexes and ages was of interest in some respects. On the basis of the presence of fully developed cysts among the weanling voles (2 cases, see males) and regarding several experiments (MLODZIMOWSKA, 1931; DOW & JARRETT

, I960; OLIVIER, 1962) showing that more than 30 days are needed for this parasite to develop in albino mice, it can be concluded that the infestation would have occurred during the early suckling age by parasite ova brought into the nest .The inversion between the number of developing and fully developed cysts in age groups 2 and 3 of females probably indicates a more equal development of females. But the males can be supposed to be more sensitive to an oncosphera invasion in the early phase of the infestation, resulting in a greater degree of mortality and a smaller number of manifested strobilocercosis. (The home range - area of activity - is much greater in males - even of juvenil age - than in females (REICHSTEIN

, 1951), meaning theoretically a greater exposure to the infestation. According to DOW and JARRETT the male mice were more disposed to the infestation, OLIVIER experimented only on males. According to MLODZIATTOWSKA, the juvenil mice were much more seriously affected by the infestation. The symptoms of illness and generally the deaths following a few days after infestation were also experienced by these authors.) 3) The above conclusion is confirmed by the investigation of the intensity of infestation. According to the numbers of developing cysts, 29 males were infested by one and 20 others by