In 3-quart saucepan, melt butter over medium heat. Add 1/2 cup sliced green onions; cook and stir until tender. Stir in flour, celery salt and pepper; cook 2 minutes, stirring occasionally.
Gradually add milk, cooking and stirring constantly over medium heat until mixture is slightly thickened. Stir in crabmeat, cream and sherry; cook just until thoroughly heated, stirring frequently. Sprinkle individual servings with grene onions.