diff --git a/longs/forms.py b/longs/forms.py
index 51438920..49092cc9 100755
--- a/longs/forms.py
+++ b/longs/forms.py
@@ -201,7 +201,7 @@ SeriesFormSet = inlineformset_factory(
 
 LongFormSet = inlineformset_factory(
     LongSeries,
-    Long,
+    Long.series,
     exclude=[],
     can_delete=True,
     extra=0,