[Physiological age of the fleas and the analysis of age structure of natural population of Xenopsylla gerbilli Wagn].

A new six-graded scale is suggested instead of five-graded one proposed earlier (Kunitskaya, 1960). Analysis of the reproduction and age composition of the natural population of X. gerbilli with a use of the suggested scale enabled the authors to find out regularities in the reproduction, senescence and change of generations of these insects in South Pribalkhashke. It was established that one complete, one incomplete and possibly third partial generation develop in this region for a year.