hornbug

from The Century Dictionary.

• noun A very common North American beetle, Passalus cornutus, of the family Lucanidæ, of large size, elongate form, and shining black color with pitch-black legs, the elytra suleate with regularly impressed lines of punctures, and the head armed with a stout curved horn.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) A large nocturnal beetle of the genus Lucanus (as Lucanus capreolus, and Lucanus dama), having long, curved upper jaws, resembling a sickle. The grubs are found in the trunks of old trees.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun zoology A large nocturnal beetle of the genus Lucanus, with long, curved upper jaws resembling a sickle, and whose grubs are found in the trunks of old trees.