Tick. Coloured scanning electron micrograph (SEM) of the underside of a tick (order Ixodida) showing its mouthparts (top centre). The mouthparts of a tick consist of three visible components. The two outer jointed parts are highly mobile palps. Between the palps is a rod-shaped structure, the hypostome. The palps do not enter the skin of the host while the tick is feeding, while the hypostome is inserted into the host's skin. The backward-pointing projections prevent easy removal of the tick.