Labium Synonyms

The mouth parts are well developed, consisting of an upper lip, powerful mandibles, maxillae with three-jointed palpi, and a deeply quadrifid labium or lower lip with three-jointed labial palpi.

Next the larvae make their way into the connective tissue in the pro-thorax, and ultimately bore a channel into the base of the piercing apparatus and come to rest between the hypopharynx and the labium.

The larvae of this parasite develop in the Malpighian tubules of the insect; at a certain stage they cast their cuticle and make their way into the space - part of the haemocoel - found in the labium.

The inner lobe (lacinia) of the first maxilla terminates in an articulated hook, while in the second maxillae (labium) both inner and outer lobes ("ligula" and "para-glossae") are much Gyrinus sulcatus reduced.

The maxillae of the hinder pair become more or less fused together to form a " lower lip " or labium, and the segment of these appendages is, in some insects, only imperfectly united with the head-capsule.