The tracheal mite (Acarapis woodi ) is an internal parasite of the honey bee and lives in the respiratory system. The mites invade the trachea (breathing tubes) in the thorax of the adult bee, where they feed and reproduce. Tracheal mites are not a problem during the summer, but become a serious problem in the winter. High infestations of tracheal mites greatly increase the likelihood of colony death. Diagnosis of a tracheal mite problem is difficult, especially since there are no obvious or reliable external symptoms that are specific to the disease. A positive acarine diagnosis can only be made in the laboratory with the aid of a microscope. The procedure makes it difficult for most beekeepers to do their own diagnosis, but the chances are very good that all colonies are infected to at least some degree. Hence we tend to recommend treatment for almost all hives.