How to install Windows 8.1 on MacBook Pro from USB?
Non-retina display MacBooks cannot boot anything other than OS X from a USB flash drive.  It's a limitation in the firmware.  Apple fixed this with the retina models because they have no optical drive, meaning USB is the ONLY way to install Windows.  On a retina display MacBook, the Boot Camp assistant even makes a USB flash drive for you the same as Rufus does.  However, they never backported this fix to non-retina models (and the Boot Camp assistant on non-retina models does not have the USB option).

The only way to boot a USB stick for the purpose of installing Windows is to use rEFInd and bless the rEFInd directory as your startup folder (which itself must be done from the command line as the Startup Disk control panel won't even show it as an option).

rEFInd will then take over the boot process and will allow you to boot to USB media.  If you don't like rEFInd you can remove it after Windows is installed.  You will then see Windows and OS X as options in the Startup Disk control panel.

Here is a link to the rEFInd home page, and here's how to install and bless the rEFInd directory.

NOTE:  Use Disk Utility to create yourself a FAT-formatted partition on the disk BEFORE you attempt to install Windows.  This will create the hybrid MBR that Windows needs to boot.  You can reformat it NTFS during the Windows install.  I you already have an NTFS partition (as your screenshot above shows), you can skip this step as you already have the hybrid MBR created.