Dr. Kassai Tibor szerk.: Parasitologia Hungarica 2. (Budapest, 1969)

yet had occasion to collect the material of a mole burrow, though the rich flea fauna of its nest has attracted the attention of several research workers (OUDEMANS, 1913; WAGNER, 1936). Recently ROSICKY (1937), SMIT (1962), and JTJRIK (1968) from an investigation of considerable material established the presence of many flea species,both on the animal and in its nest.Regretably, none of these authors, with the exception of ROSICKY have published information on the flea populations of the several hosts and their nests but have merely discussed the occurrence of the flea species observed. Plea common occurrences on the bat It might be assumed that several types of flea population would occur on bats because certain bat species aggregate in masses in both their winter and summer quarters. True

,in most colonies only members of a given species are closely associated with each other but there would still be more possibilities for transmission of divers flea species than in the case of other mammalian groups. However, I found only six kinds of common occurrences of fleas, among which only two occurred in three and six cases, respectively (serial numbers 71 and 74), while the four other compositions were observed in only one case each. The most frequent species of the cases of coexistence is Isch nopsyllus hexactenus (Kolenati), which., occurred in four variations in eleven cases. The occurrence of I.intermedius (Rothschild) with other species is fairly common having been found in three variations on eight occasions. In addition there are other, somewhat occasional, comron occurrences of smaller specific numbers and rather rare appearence. Thus, besides Monopsyllus sciurorum sciurorum (Schrank), the specific flea of the squirrel (Sciurus vulgaris fuscoater Altum) and its nest, one may occasionally find in its company Tarso- psylla octodecimdentata octodecimdentata (Kolenati), a species rather rare in Hungary. The various dormouse species show a de-