Name that starter relay wire

Hey guys:

Quick question:

On my '71 Plymouth, there is a wire connecting to the starter relay behind the battery that I forgot where it went.

It is attached with the screw that takes a flathead screwdriver. There are two wires connecting to that, the other leads to the starter sol.

If I touch this wire in question to positive, it will run the starter and start the engine. I'm pretty sure it was there before, but I could have added it.