The man wearing tails at center right is the only man out of uniform in the picture.
From en.gallerix.ru/album/Hermitage-5.
The overall visual impression, swirling domes, is the same as for a crinoline era ball. The bustle era was noteworthy for square necklines, but the Ladies are wearing other necklines here.
Keywords: 1873, Zichy, Russian, long curly coiffure, long straight coiffure, tiara, ribbon headdress, modesty piece, cap sleeves, bows, bustle, over-skirt, ruffles, under-skirt, flounces, neck band, bracelets, gloves