There are few reports of mites of the Subfamily Labidophorinae in North America, and only one in which the specimens were identified to species even though members of this group often are very common on small mammals. It would appear that the scarcity of reports is because of insuffi.cient collecting rather than scarcity of mites. Four species have been found during the present work. They are Labidophorus soricis Oudemans, I9I5, primarily of Cryptotis parva, Dermacarus hypudaei Koch, I84I, abundant on Zapodids but also found on other small mammals, Dermacarus heptneri Zachvatkin, I94I found on Mus musculus, and Dermacarus ondatrae sp. n. found on Ondatra zibethica.