The body is firm, oval or boatlike in form, and usually dark colored with a bronzelike luster
These beetles live mostly on the surface of water, and move about with great celerity in a gyrating, or circular, manner, but they are also able to dive and swim rapidly
A mediæval instrument for punishing petty offenders, being a kind of wooden cage turning on a pivot, in which the offender was whirled round with great velocity