Drush and MAMP3: cannot connect to database
Thanks for those suggestions.  I inadvertently stumbled on  a solution.  I'm no expert here, so there could (and probably are) reasons why this isn't a good idea but I'll share it anyway.

I simply created a sim-link by doing the following:
cd /tmp
sudo ln -s /Applications/MAMP/tmp/mysql/mysql.sock mysql.sock

Worked like a charm.