A band of South American Gaucho, from the Argentine Republic, arrived at Southhampton on Saturday. These horsemen from the interior of South America have been twenty-seven days at sea, and come from seventeen days journey in the interior, to join Buffalo Bill's Wild West, making the sixth delegation of the Congress of Horsemen of the world, which Colonel Cody intends to give at the great World's Fair, Chicago; the International Horticultural Exhibition at Earl's Court, London, being the organising point.