James, 3rd Marquess of Queensberry

James, eldest son of James, 2nd Duke of Queensberry, was criminally insane and was kept under lock and key at all times. Legend has it that while the Duke was away celebrating the "Act of Union", James escaped his locked quarters, captured and roasted a small kitchen boy, and was discovered trying to eat the poor lad. Critics of the "Act of Union" claimed it a "judgement on the Duke for his odious share in the Union." James was allowed to inherit the Marquissate and Earldom of Queensberry but, due to his mental state, did not succeed to the Dukedom which was passed to his younger brother Charles. 

James died in 1715, and his titles also passed to his younger brother, Charles, 3rd Duke of Queensberry.