The Collaborative International Dictionary of English v.0.48:

Longicornia \Lon`gi*cor"ni*a\, n. pl. [NL., fr. L. longus long +
   cornu horn.] (Zool.)
   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.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Locust \Lo"cust\, n. [L. locusta locust, grasshopper. Cf.
   Lobster.]
   1. (Zool.) Any one of numerous species of long-winged,
      migratory, orthopterous insects, of the family
      Acridid[ae], allied to the grasshoppers; esp., (Edipoda
      migratoria, syn. Pachytylus migratoria, and Acridium
      perigrinum, of Southern Europe, Asia, and Africa. In the
      United States the related species with similar habits are
      usually called grasshoppers. See Grasshopper.
      [1913 Webster]

   Note: These insects are at times so numerous in Africa and
         the south of Asia as to devour every green thing; and
         when they migrate, they fly in an immense cloud. In the
         United States the harvest flies are improperly called
         locusts. See Cicada.
         [1913 Webster]

   Locust beetle (Zool.), a longicorn beetle (Cyllene
      robini[ae]), which, in the larval state, bores holes in
      the wood of the locust tree. Its color is brownish black,
      barred with yellow. Called also locust borer.

   Locust bird (Zool.) the rose-colored starling or pastor of
      India. See Pastor.

   Locust hunter (Zool.), an African bird; the beefeater.
      [1913 Webster]

   2. [Etymol. uncertain.] (Bot.) The locust tree. See Locust
      Tree (definition, note, and phrases).
      [1913 Webster]

   Locust bean (Bot.), a commercial name for the sweet pod of
      the carob tree.
      [1913 Webster]