Acarapis dorsalis, is an external parasite infecting the dorsal groove of a honey bee's thorax. These mites are generally less than 175 micrometres (0.007 in) long, and can only be identified under a microscope. A. dorsalis can be found exclusively along the dorsal scutoscutellar groove of its host bee's thorax. These mites feed on the bee's haemolymph from here. Two other parasitic bee mites resembling the tracheal mite are A. externus, and A. woodi.