Mitonyssoides stercoralis Yunker, Lukoschus, and Giesen, 1990 is recognized as a senior subjective synonym of Coprolactistus whitakeri Radovsky and Krantz, 1998, new synonymy, and therefore Mitonyssoides Yunker, Lukoschus, and Giesen, 1990 is a senior synonym of Coprolactistus Radovsky and Krantz, 1998, new synonymy. By the species synonymy reported in this work, the known range of bat guano associations for M. stercoralis is extended to include both Vespertilionidae and Molossidae. Systematic and distributional implications of the synonymies are discussed.