diff --git a/Lib/exceptions.py b/Lib/exceptions.py
index 2963c04..e943f7b 100644
--- a/Lib/exceptions.py
+++ b/Lib/exceptions.py
@@ -11,10 +11,11 @@
 tricky uses of IOError may break, but the most common uses should work.
 
 Here is a rundown of the class hierarchy.  You can change this by editing this
-file, but it isn't recommended.  The class names described here are expected
-to be found by the bltinmodule.c file.  If you add classes here, you must
-modify bltinmodule.c or the exceptions won't be available in the __builtin__
-module, nor will they be accessible from C.
+file, but it isn't recommended because the old string based exceptions won't
+be kept in sync.  The class names described here are expected to be found by
+the bltinmodule.c file.  If you add classes here, you must modify
+bltinmodule.c or the exceptions won't be available in the __builtin__ module,
+nor will they be accessible from C.
 
 The classes with a `*' are new since Python 1.5.  They are defined as tuples
 containing the derived exceptions when string-based exceptions are used.  If
@@ -23,9 +24,9 @@
 
 Exception(*)
  |
+ +-- SystemExit
  +-- StandardError(*)
       |
-      +-- SystemExit
       +-- KeyboardInterrupt
       +-- ImportError
       +-- EnvironmentError(*)