CREATE TABLE table_2417340_3 (state__class_ VARCHAR2, date_of_successors_formal_installation VARCHAR2)

List all state classes when successors were formally installed on June 22, 1868.
SELECT state__class_ FROM table_2417340_3 WHERE date_of_successors_formal_installation = "June 22, 1868"
SELECT "state__class_" FROM "table_2417340_3" WHERE "June 22, 1868" = "date_of_successors_formal_installation"