diff --git a/src/hashset.hpp b/src/hashset.hpp
index cdc730bf..6efd4dd9 100644
--- a/src/hashset.hpp
+++ b/src/hashset.hpp
@@ -35,6 +35,7 @@ public:
   HashSet()
   {
     _set = kh_init(hashset);
+    str_set_init(&_str_set);
   }
 
   ~HashSet()