diff --git a/tornado/web.py b/tornado/web.py
index 092306b0..b79399ad 100644
--- a/tornado/web.py
+++ b/tornado/web.py
@@ -1126,7 +1126,7 @@ class Application(object):
         handlers = self._get_host_handlers(request)
         if not handlers:
             handler = RedirectHandler(
-                request, "http://" + self.default_host + "/")
+                self, request, "http://" + self.default_host + "/")
         else:
             for spec in handlers:
                 match = spec.regex.match(request.path)