Hi Randy,
As viewed in this photo, the emitter is on the right and the phototransistor is on the left.
In bright light, you can also tell them apart as the phototransistor is black (visible light filter), and the emitter is blue/green.
All purple wires are Gnd or minus.
This is not intuitive at all, and thanks for pointing it out. We'll include a card in future shipments, with wiring info.
Thanks!
-Josh