Cell that may be present in the base of the wing and that is formed by joining of the second anterior cubital vein (CuA2) and the first anal vein (A1). If these two veins are approximated but not closing the cell (for example in Diastatidae) the cell is open. If either or both veins are missing, or if both veins run to thw wing margin, the cell is absent. Also known as: anal cell, cell cup.