Sorry for the title, but how can I name it better?

My problem is this. I try to rig a pair of boots. Everything works fine so far but in the end I have one bone I can not make go away. Ironically it looks somewhat ... er ... private.

Please have a look at the screenshot.

Can anyone tell me how to rig my boots without all the other bones and specially without this mentioned bone?

 

Thank you very much