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pedipalps In Arachnida, the second of the six pairs of appendages possessed by the prosoma. They have become walking legs, or true palps, in those arachnids that have large chelicerae (Araneae, Palpigradi, Solifugae, and many Opiliones and mites). In orders with small chelicerae (Scorpiones, Amblypygi, Uropygi, and Pseudoscorpiones) the pedipalp has become modified to form a large raptorial organ. The pedipalps are universal tools for the killing and manipulation of prey, as well as for defence and digging. In all arachnids they also serve as tactile and olfactory organs. In the spiders, the pedipalps guide food into the mouth, and the pedipalpal tarsus has become modified in males to form a complex copulatory structure (often used by taxonomists as a means of species identification).