Melt butter in skillet. Add flour and stir until smooth. Add milk and cook until thick. Remove from heat and add mayonnaise, mustard, Worcestershire sauce, onion. seafood seasoning, salt and pepper to taste. Fold in crab meat. Put in greased baking dish. Top with buttered bread cubes and bake until golden brown in a 350 degree oven. This can be made and put in the freezer for winter usage.