diff --git a/grudge/symbolic/dofdesc_inference.py b/grudge/symbolic/dofdesc_inference.py
index 832c6a0371764cceef497e67a4a9c27300a5825a..7e1de6058e046154d2f5a254cb0f4c103f1eb09b 100644
--- a/grudge/symbolic/dofdesc_inference.py
+++ b/grudge/symbolic/dofdesc_inference.py
@@ -48,11 +48,11 @@ def unify_dofdescs(dd_a, dd_b, expr=None):
         elif dd_b.domain_tag == DTAG_SCALAR:
             return dd_a
         else:
-            raise ValueError("mismatched domain tags" + loc_str)
+            raise ValueError("mismatched domain tags " + loc_str)
 
     # domain tags match
     if dd_a.quadrature_tag != dd_b.quadrature_tag:
-        raise ValueError("mismatched quadrature tags" + loc_str)
+        raise ValueError("mismatched quadrature tags " + loc_str)
 
     return dd_a