The structure of sensilla on the palptarsus and tarsus I of Tetranychus truncatus Ehara was examined with light, scanning and transmission electron microscopy. A small, peg-shaped sensillum (solenidion), two elongate sensilla with blunt ends (eupathidia) and three hair-like setae are found on the palptarsus. The solenidion and two eupathidia stained with silver nitrate indicating their porosity and TEM micrographs of these two types showed a hollow seta and dendrites in the lumen. These are characteristics of typical chemosensitive sensilla. The hair-like sensilla lack any staining, which denotes the non-porosity of sensilla and they are solid, having no lumen. These characteristics are typical of mechanosensitive sensilla. The sensilla of tarsus I of T. truncatus are chemoreceptors and mechanoreceptors similar to that occurs on the palptarsus. The two elongate and tapered solenidia with distinct sockets forming part of the duplex setae were stained with silver nitrate which indicated their porosity. The three eupathidia were also stained with silver nitrate, revealing their porosity. These sensilla situated on the palptarsus and tarsus I are the structures for perceiving chemicals in the environment involved in mating, feeding and host plants specificity behaviors of mites.