What is "hornbug"

Hornbug \Horn"bug`\, n. (Zo["o]l.) 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.

n. 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.