Preheat oven to 400 degrees. In a bowl, mix blueberries, 1 1/4 cup sugar, lemon juice, tapioca. Pour into unbaked pie shell. Sprinkle with cinnamon, dot with butter. Cover with top crust, flute edges and vent top.
Sprinkle top crust with 1 tablespoon sugar and bake for 40 to 50 minutes. If crust starts to darken before pie is done, cut foil strips to lay over edges.