Rhadine persephone  Rhadine persephone is a rare species of beetle known by the common name Tooth Cave ground beetle. It is endemic to Texas in the United States, where it occurs in a network of caves outside Austin. It is a federally listed endangered species of the United States. This troglobite is a reddish-brown beetle about 7 or 8 millimeters long. Its eyes are rudimentary. It lives on the silt on the cave floors, where it runs around seeking food. It digs up and consumes cricket eggs. This beetle has been found at 54 locations in karst caves in Travis and Williamson Counties in Texas; three of these locations have since been destroyed. The beetle's survival is threatened by the destruction of its cave habitat, the degradation of the caves by pollution and garbage, and the invasion of fire ants.