diff --git a/src/wormhole/_boss.py b/src/wormhole/_boss.py
index ec6c845..a5cb790 100644
--- a/src/wormhole/_boss.py
+++ b/src/wormhole/_boss.py
@@ -205,8 +205,8 @@ class Boss(object):
         self._did_start_code = True
         self._C.set_code(code)
 
-    def dilate(self, no_listen=False):
-        return self._D.dilate(no_listen=no_listen)  # fires with endpoints
+    def dilate(self, transit_relay_location=None, no_listen=False):
+        return self._D.dilate(transit_relay_location, no_listen=no_listen)  # fires with endpoints
 
     @m.input()
     def send(self, plaintext):
diff --git a/src/wormhole/wormhole.py b/src/wormhole/wormhole.py
index 1e5509d..1db12d7 100644
--- a/src/wormhole/wormhole.py
+++ b/src/wormhole/wormhole.py
@@ -193,10 +193,10 @@ class _DeferredWormhole(object):
             raise NoKeyError()
         return derive_key(self._key, to_bytes(purpose), length)
 
-    def dilate(self, no_listen=False):
+    def dilate(self, transit_relay_location=None, no_listen=False):
         if not self._enable_dilate:
             raise NotImplementedError
-        return self._boss.dilate(no_listen)  # fires with (endpoints)
+        return self._boss.dilate(transit_relay_location, no_listen)  # fires with (endpoints)
 
     def close(self):
         # fails with WormholeError unless we established a connection