Preheat oven to 350 degrees. Blend pie crust mix, the 1/4 cup of sugar and 1 of the eggs in medium-size bowl with a pastry blender. Pat dough gently in to a greased 13x9x2 inch baking pan. Bake in a moderate (350 degree) oven for 10 minutes. Remove to wire rack, leaving oven on. Beat the 3 remaining eggs and the 1 cup sugar in a medium-size bowl with electric mixer until light and fluffy. Beat in lemon rind and juice and flour; pour mixture over pie crust. Return to oven; bake 15 minutes longer. Beat egg whites with cream of tartar in a medium-size bowl with an electric mixer until frothy. Beat in remaining 3 tablespoons sugar, 1 tablespoon at a time, until meringue forms stiff peaks. Remove pan from oven. Raise oven temperature to very hot (450 degrees). Spread meringue mixture over lemon mixture. Return to oven and bake 5 minutes more or until meringue peaks are golden brown. Cool on wire rack. Cut with a wet knife into bars
