"Ophiuchus Wilkes," he said, finishing her sentence. Everyone knew of the obscenely wealthy and prominent Wilkeses in the pureblood community, which was why he was so amused at being mistaken for a Muggle.
As for her, she looked vaguely familiar. She was older than he, so she had probably graduated Hogwarts some years ago, and had probably changed in appearance since then as well. Wilkes was guessing that she had been a Slytherin, probably from one of the old pureblood families, which meant he probably knew of her, even if he didn't recognize her.
He gave a slight, gentlemanly bow. "The pleasure is mine, Miss...?"