diff --git a/mitogen/core.py b/mitogen/core.py
index edc15f68..ad9511cc 100644
--- a/mitogen/core.py
+++ b/mitogen/core.py
@@ -909,21 +909,21 @@ class Latch(object):
     closed = False
 
     def __init__(self):
-        self.lock = threading.Lock()
-        self.queue = []
-        self.wake_socks = []
+        self._lock = threading.Lock()
+        self._queue = []
+        self._waiters = []
 
     def close(self):
-        self.lock.acquire()
+        self._lock.acquire()
         try:
             self.closed = True
-            for wsock in self.wake_socks:
+            for wsock in self._waiters:
                 self._wake(wsock)
         finally:
-            self.lock.release()
+            self._lock.release()
 
     def empty(self):
-        return len(self.queue) == 0
+        return len(self._queue) == 0
 
     def _tls_init(self):
         if not hasattr(_tls, 'rsock'):
@@ -935,54 +935,54 @@ class Latch(object):
         _vv and IOLOG.debug('%r.get(timeout=%r, block=%r)',
                             self, timeout, block)
 
-        self.lock.acquire()
+        self._lock.acquire()
         try:
             if self.closed:
                 raise LatchError()
-            if self.queue and not self.wake_socks:
-                _vv and IOLOG.debug('%r.get() -> %r', self, self.queue[0])
-                return self.queue.pop(0)
+            if self._queue and not self._waiters:
+                _vv and IOLOG.debug('%r.get() -> %r', self, self._queue[0])
+                return self._queue.pop(0)
             if not block:
                 raise TimeoutError()
             self._tls_init()
-            self.wake_socks.append(_tls.wsock)
+            self._waiters.append(_tls.wsock)
         finally:
-            self.lock.release()
+            self._lock.release()
 
         _vv and IOLOG.debug('%r.get() -> sleeping', self)
         rfds, _, _ = restart(select.select, [_tls.rsock], [], [], timeout)
         assert len(rfds) or timeout is not None
 
-        self.lock.acquire()
+        self._lock.acquire()
         try:
-            self.wake_socks.remove(_tls.wsock)
+            self._waiters.remove(_tls.wsock)
             if self.closed:
                 raise LatchError()
             if not rfds:
                 raise TimeoutError()
             assert _tls.rsock.recv(1) == '\x7f'
             try:
-                _vv and IOLOG.debug('%r.get() wake -> %r', self, self.queue[0])
-                return self.queue.pop(0)
+                _vv and IOLOG.debug('%r.get() wake -> %r', self, self._queue[0])
+                return self._queue.pop(0)
             except IndexError:
                 IOLOG.exception('%r.get() INDEX ERROR', self)
                 raise
         finally:
-            self.lock.release()
+            self._lock.release()
 
     def put(self, obj):
         _vv and IOLOG.debug('%r.put(%r)', self, obj)
-        self.lock.acquire()
+        self._lock.acquire()
         try:
             if self.closed:
                 raise LatchError()
-            self.queue.append(obj)
-            if self.wake_socks:
+            self._queue.append(obj)
+            if self._waiters:
                 _vv and IOLOG.debug('%r.put() -> waking wfd=%r',
-                                    self, self.wake_socks[0].fileno())
-                self._wake(self.wake_socks[0])
+                                    self, self._waiters[0].fileno())
+                self._wake(self._waiters[0])
         finally:
-            self.lock.release()
+            self._lock.release()
 
     def _wake(self, sock):
         try:
@@ -996,7 +996,7 @@ class Latch(object):
         wsock = getattr(_tls, 'wsock', None)
         return 'Latch(%#x, size=%d, t=%r, r=%r, w=%r)' % (
             id(self),
-            len(self.queue),
+            len(self._queue),
             threading.currentThread().name,
             rsock and rsock.fileno(),
             wsock and wsock.fileno(),