diff --git a/pymbolic/mapper/c_code.py b/pymbolic/mapper/c_code.py
index 26fa4e3b79944253ebf2c366d9e1da45da554343..d30849eafae4e61fe18862654a84c04e8f5b9fd0 100644
--- a/pymbolic/mapper/c_code.py
+++ b/pymbolic/mapper/c_code.py
@@ -18,7 +18,7 @@ class CCodeMapper(SimplifyingSortingStringifyMapper):
         import numpy
         if isinstance(x, complex):
             return "std::complex<%s>(%s, %s)" % (
-                    complex_constant_base_type,
+                    self.complex_constant_base_type,
                     self.constant_mapper(x.real), 
                     self.constant_mapper(x.imag))
         else: