How to access the USB2.0-Serial port on my MacBook Pro.

I'm using an Arduino Mega 2560 micro controller to run a 3D printer. It has a serial connection to my MacBook Pro (El Capitan OS 10.11) via Mac's USB port.

The Mac System Report shows the port (USB2.0-Serial) but I end up only being able to use /dev/**.Bluetooth-Incoming-Port, which doesn't allow communication with the board. How do I get the serial port to show up in TOOLS>PORT on the Mac in the Arduino software?