diff --git a/numpy/f2py/rules.py b/numpy/f2py/rules.py
index 37cc76ec2f3c..6a1f5ae6e5ec 100644
--- a/numpy/f2py/rules.py
+++ b/numpy/f2py/rules.py
@@ -15,7 +15,7 @@
     get_b_from_python
     if (successful) {
 
-      call_fortran
+      callfortran
       if (successful) {
 
         put_a_to_python