diff --git a/src/hashset.hpp b/src/hashset.hpp
index c9290676..a1b9fb93 100644
--- a/src/hashset.hpp
+++ b/src/hashset.hpp
@@ -58,7 +58,7 @@ public:
   HashSet()
   {
     _set = kh_init(hashset);
-    u64_set_init(&_str_set);
+    u64_set_init(&_u64_set);
   }
 
   ~HashSet()