Courtesy Rani, Reply 532:

I believe the lady on the far left is
Teresa of Naples and Sicily,
Empress of Brazil, wife of D. Pedro II. She would be the only other "western" Empress at the time with the Queen Augusta of Prussia not becoming German Empress until 1871 and by that time Eugenie was no longer an Empress. Queen Victoria was not declared Empress of India until 1876 and I doubt either the Empress Cixi of China or the Empress of Japan would be included in such a picture. Anyway, the lady on the left looks like Empress Teresa.
-Duke of NJ