labium

biology

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In insect: Head
…form the lower lip, or labium. Sometimes a median tonguelike structure, called the hypopharynx, arises from the floor of the mouth.
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In heteropteran: Mouthparts
…composed of a troughlike, four-segmented labium in which lie four stylets; these are modified mandibles and maxillae. Each of the hairlike maxillae has two major grooves plus minor grooves and ridges along its median surface. When brought together and locked by the minor grooves and ridges, the two major grooves…
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