diff --git a/tractor/_trionics.py b/tractor/_trionics.py
index 19e7f97..427a6f9 100644
--- a/tractor/_trionics.py
+++ b/tractor/_trionics.py
@@ -65,8 +65,8 @@ class ActorNursery:
             fs_deats = addr, alive_fd, pid, st_pid, st_fd = (
                 fs._forkserver_address,
                 fs._forkserver_alive_fd,
-                fs._forkserver_pid,
-                semaphore_tracker._semaphore_tracker._pid,
+                getattr(fs, '_forkserver_pid', None),
+                getattr(semaphore_tracker._semaphore_tracker, '_pid', None),
                 semaphore_tracker._semaphore_tracker._fd,
             )
         else: