The labial palps borne on the sides of labium are the counterparts of maxillary palps. The maxillae have lobes, and the labial palps (sensory structures on the labium) are knob-shaped. Unlike the mandibles, but like the labium, the maxillae bear lateral palps on their stipites. The mouth parts contain a maxillae, a labium, and a set of mandibles. In place of the labium, crustaceans possess a second pair of maxillae. The labium encloses all other mouthparts like a sheath. The maxillae form needle-like structures, called stylets, which are enclosed by the labium. The labium is innervated by the sub-esophageal ganglia. The term derives from Latin "nasus" for "nose" and "labium" for "lip". The stylet is capable of piercing tissues and sucking liquids, while the labium supports it. At the back side of the mouth is the labium or lower lip. The hypopharynx is a somewhat globular structure, arising from the base of the labium. The larvae have silk glands which are located on the labium. This results into a global transversal motion of the jet at the labium. These two elements are coupled at the flue exit and at the labium.