Does anybody know how to hide these in Mail's sidebar?

[Nghia Nguyen]

I notice in Mail.app, on the sidebar they show these at the bottom and I find them pretty annoying since the mailboxes already show me my mails. Is there any way to turn off/hide those (in red box)?

Thanks!

 

[Matthew Yohe]

The "mailboxes may already show you your mails" but they don't show you additional folders associated with those accounts. How would you get to those?