Dy*nas"ti*dan (?), n. [Gr. &?;, fem. of &?;. See Dynast. The name alludes to the immense size of some species.] (Zoöl.) One of a group of gigantic, horned beetles, including Dynastus Neptunus, and the Hercules beetle (D. Hercules) of tropical America, which grow to be six inches in length.