How can I tell what AnimationState mecanim Animator is in from script?

I'd like to do some specific code-side stuff when my Animator enters certain states, but I can't figure out how to tell what state it's in from script. For example, I have an AnimationState called "Ambulate" - it looks like I should be able to do something like -

 AnimatorStateInfo asi = myAnim.GetCurrentAnimatorStateInfo(0);
 int ambulateHash = Animator.StringToHash( "Ambulate" );   // or asi.IsName("Ambulate")
 if( asi.nameHash == ambulateHash )
 {
   // ... do my special stuff ...
 }

But neither of those work. Any help?