Problems with third_party/ion_auth

I have installed and worked with ion_auth by placing all the ion_auth files among my other files, like placed the controller Auth.php in my own application/controllers folder. 

Now, I like to try to have it installed as a third_party,  separated from the rest, so now I placed the ion_auth package in applications/third_party/ion_auth/.

So, how can I access a controller in that third_party folder?
I try to tell codeigniter that I have all Ion_auth stuff in my third_party folder by telling this to autoload.php:

So in my browser, I try "localhost/myApp/index.php/auth"

But all I get is "404 Page not found".