HELMINTHS OF MICROTINAE IN WESTERN MONTANA

Seventeen species of helminths were found in 134 voles of 5 species (Phenacomys intermedius, Clethrionomys gapperi, Microtus longlcaudus, Microtus montanus, Microtus pennsylvanicus) collected in 1964 and 1965 in western Montana. Ten new records for North America and 26 new records for Montana were recorded. Seasonal patterns of infection were noted in Quinqueserialis quinqueserialis and Paranoplocephala infrequens. The taxonomy of the nematode Heligmosomum dubius (Baylis, 1926) Tenora, 1958 was discussed. The first record of Aspiculuris tetraptera in microtine rodents and the second record of Pelodera sp. in the orbits of North American rodents were reported. A high frequency of mixed infections of the digestive tract was found, usually accompanied by a pronounced stratification of the helminths within the tract.