Using Subdomain with MAMP

I could use some help creating subdomains in MAMP. Here's where I'm at.

I have MAMP installed... it's working fine with localhost.

To create the subdomains II've followed this tutorial but it doesn't seem to work.
http://wpdreamer.com/2013/08/how-to-setup-a-localhost-wordpress-sub-domain-multisite-environment/#configure-mamp

I'm getting server not found errors attempting to view.
localhost.dev and localhost.dev/wordpress

Here's my host file:
http://screencast.com/t/WIMfOaolf6A

Thanks!
Chris