Preheat oven to 350 degrees F. In a large heavy skillet cook onion, garlic, celery, carrot, and scallion in butter over moderate heat, stirring, 5 minutes. Cook vegetables, covered, stirring occasionally, until carrot it tender, about 5 minutes more. Stir in salt and pepper, Worcestershire sauce, and 1/3 cup of ketchup and cook, stirring, 1 minute. In a large bowl combine well vegetables, meats, bread crumbs, eggs, and parsley. In a shallow baking pan form mixture into a 5" x 10" oval loaf and spread remaining 1/3 cup ketchup over loaf. Bake meat loaf in oven 1 hour, or until a meat thermometer inserted in center registers 155 degrees F.