[Fertility of the flea, Xenopsylla gerbilli Minax, that parasitizes the great gerbil (Aphaniptera)]. / O plodovitosti blokh Xenopsylla gerbilli Minax, parazitiruiushchikh na bol'shoi peschanke (Aphaniptera).

It has been established experimentally that the fecundity of females of Xenopsylla gerbilli minax is wavy in its character from the beginning to end of their reproduction (peaks are replaced by falls). In spring and summer the egg laying proceeds on the 2nd--3rd day after the first bloodsucking of fleas and lasts to the end of their life. In autumn the first eggs develop on the 4th--6th day and do not develop at all at the end of the life. In winter months the egg production is somewhat slowed down but with the coming of spring become more intensive. Progeny obtained from one female during the experiment varies, depending on the conditions of the maintenance, from 20 to 130 individuals.

[Effect of the prolonged contact of a flea population with plague bacteria on the infective activity of vetors]. / Vliianie dlitel'nogo kontakta populiatsii blokh s bakteriiami chumy na zarazhaiushchuiu aktivnost' perenoschikov

Results of the experimental infection of fleas (X. cheopis) with the plague agent after their long (2.5 years, 19 generations) feeding on infected white mice showed no difference in the infection activity of these insects as compared to control ones. The authors question the hypothesis according to which a low frequency of protein-formation in some species of fleas is due to their long contact with the plague agent in the historical past.