Line the bottom and sides of a 9-inch pie plate with a layer of alternating vanilla wafer crumbs and banana slices.
To Make Pudding: In a medium saucepan, combine 1 1/2 cups sugar with flour. Mix well, then stir in half the milk. Beat egg yolks and whisk into sugar mixture. Add remaining milk and butter or margarine.
Place mixture over low heat and cook until thickened, stirring frequently. Remove from heat and stir in vanilla extract. Pour half of pudding over vanilla wafer and banana layer while still hot.
Make another layer of alternating vanilla wafers and banana slices on top of pudding layer. Pour remaining pudding over second wafer and banana layer.
To Make Meringue: In a large glass or metal bowl, beat egg whites until foamy. Gradually add 1/4 cup sugar, continuing to beat until whites are stiff. Spread meringue into pie pan, making sure to completely cover pudding layer.
Bake in preheated oven for 15 minutes, just until meringue is browned. Chill before serving.