| abstract | A new species of cheyletid mite, Bak ozarkensis, from Missouri including both sexes, two nymphal stages and the larva, is described and illustrated. These stages were collected from the basal bark, stump wood and root dood of dead American elm, red oak, shagbark hickory and Osage orange material. This is the first time that all the life stages exclusive of eggs has been described for any species of the genus. A revised key to the known world species is presented. |