The mandible (from Latin: mandibula or mandĭbŭ-lum, a jaw) of an arthropod is a pair of mouthparts used either for biting or cutting and holding food. Mandibles are often simply referred to as jaws. Mandibles are present in the extant subphyla Myriapoda (millipedes and others), Crustacea and Hexapoda (insects etc.). These groups make up the clade Mandibulata, which is currently believed to be the sister group to the rest of arthropods, the clade Arachnomorpha (Chelicerata and Trilobita).
Unlike the chelicerae of arachnids, mandibles can often be used to chew food. Mandibulates also differ by having antennae, and also by having three distinct body regions: head, thorax and abdomen. (The cephalothorax (or prosoma) of chelicerates is a fusion of head and thorax.)
Insect mandibles are as diverse in form as their food. For instance, grasshoppers and many other plant-eating insects have sharp-edged mandibles that move side to side. Most butterflies and moths lack mandibles as they mainly feed on nectar from flowers.
Queen bees have mandibles with sharp cutting teeth unlike worker bees, who have toothless jaws. Male dobsonflies have slender mandibles up to 2.5 cm long, half as long as the insect's main body. Potter wasps use their mandibles to mix droplets of water with clay while constructing a nest.