Three types of setae were found on the antenna of workers of C. formosanus. Sensilla basiconica function as chemoreceptors. They are non-socketed, with fixed plate base, thin walled, and perforated. Pore tubules are contained within the cuticular pores of s. basiconica. The pore tubules have direct contact with the dendritic branches within the sensilla. The other sensilla are tactile mechanoreceptors. The longest setae (sensilla trichodea) are thick walled, socketed, mononeuronic, and non-perforated. The shorter mechanoreceptors (sensilla chaetica) have the same characteristics as s. trichodea, except that they are sometimes dineuronic. The numbers and distribution of the sensilla were established.