diff --git a/motor/core.py b/motor/core.py
index <HASH>..<HASH> 100644
--- a/motor/core.py
+++ b/motor/core.py
@@ -129,8 +129,7 @@ class AgnosticClient(AgnosticBaseProperties):
         else:
             io_loop = self._framework.get_event_loop()
 
-        # For Synchro's sake, add undocumented "_connect" option, default False.
-        kwargs['connect'] = kwargs.pop('_connect', False)
+        kwargs.setdefault('connect', False)
         delegate = self.__delegate_class__(*args, **kwargs)
 
         super(AgnosticBaseProperties, self).__init__(delegate)
diff --git a/synchro/__init__.py b/synchro/__init__.py
index <HASH>..<HASH> 100644
--- a/synchro/__init__.py
+++ b/synchro/__init__.py
@@ -291,7 +291,7 @@ class MongoClient(Synchro):
         self.delegate = kwargs.pop('delegate', None)
 
         # Motor passes connect=False by default.
-        kwargs.setdefault('_connect', True)
+        kwargs.setdefault('connect', True)
         if not self.delegate:
             self.delegate = self.__delegate_class__(host, port, *args, **kwargs)
PyMongo 3 renamed _connect to connect.