Longicornia \Lon`gi*cor"ni*a\, n. pl. [NL., fr. L. longus long + cornu horn.] (Zo["o]l.) A division of beetles, including a large number of species, in which the antenn[ae] are very long. Most of them, while in the larval state, bore into the wood or beneath the bark of trees, and some species are very destructive to fruit and shade trees. See {Apple borer}, under {Apple}, and {Locust beetle}, under {Locust}.