Which of these teams isn't a member of the NHL's "Original Six" era?

The Philadelphia Flyers are not a member of the NHL's Original Six era because they were established in 1967, two years after the era had already begun. The Original Six era, which lasted from 1942 to 1967, consisted of the Toronto Maple Leafs, Montreal Canadiens, Boston Bruins, Detroit Red Wings, Chicago Blackhawks, and New York Rangers. The Flyers became part of the NHL during its first expansion when six more teams were added to the league. Despite not being an Original Six team, the Flyers have since become a significant and successful franchise in their own right.