diff --git a/Lib/fontTools/ttLib/tables/C_F_F_.py b/Lib/fontTools/ttLib/tables/C_F_F_.py
index 410958188..26f8a8e9d 100644
--- a/Lib/fontTools/ttLib/tables/C_F_F_.py
+++ b/Lib/fontTools/ttLib/tables/C_F_F_.py
@@ -6,7 +6,7 @@ from . import DefaultTable
 
 class table_C_F_F_(DefaultTable.DefaultTable):
 
-	def __init__(self, tag):
+	def __init__(self, tag=None):
 		DefaultTable.DefaultTable.__init__(self, tag)
 		self.cff = cffLib.CFFFontSet()
 		self._gaveGlyphOrder = False
diff --git a/Lib/fontTools/ttLib/tables/_f_v_a_r.py b/Lib/fontTools/ttLib/tables/_f_v_a_r.py
index ab4d03ee1..cf12ce839 100644
--- a/Lib/fontTools/ttLib/tables/_f_v_a_r.py
+++ b/Lib/fontTools/ttLib/tables/_f_v_a_r.py
@@ -41,7 +41,7 @@ FVAR_INSTANCE_FORMAT = """
 class table__f_v_a_r(DefaultTable.DefaultTable):
     dependencies = ["name"]
 
-    def __init__(self, tag="fvar"):
+    def __init__(self, tag=None):
         DefaultTable.DefaultTable.__init__(self, tag)
         self.axes = []
         self.instances = []
diff --git a/Lib/fontTools/ttLib/tables/_m_e_t_a.py b/Lib/fontTools/ttLib/tables/_m_e_t_a.py
index bf70589ea..33067fd50 100644
--- a/Lib/fontTools/ttLib/tables/_m_e_t_a.py
+++ b/Lib/fontTools/ttLib/tables/_m_e_t_a.py
@@ -26,7 +26,7 @@ DATA_MAP_FORMAT = """
 
 
 class table__m_e_t_a(DefaultTable.DefaultTable):
-    def __init__(self, tag="meta"):
+    def __init__(self, tag=None):
         DefaultTable.DefaultTable.__init__(self, tag)
         self.data = {}