What's the Feminine of "Philanthropist"?

According to the New York Times, it's "socialite":

The Metropolitan Opera has received the largest individual gift in its history, a $25 million donation from the socialite Mercedes Bass and her husband, Sid R. Bass, that comes at a time of increasing financial troubles for the house.

Compare this to how a male donor (who, by the way, reneged on his gift) is treated later in the article:

In effect, the gift to the Met replaces the unfulfilled pledges of Alberto W. Vilar, an investor and arts philanthropist. The Met added Mr. Vilar's name to its Grand Tier in recognition of a $20 million pledge several years ago, then removed it when he failed to meet the pledge. Mr. Vilar has since fallen from grace with his indictment on fraud charges in June.

Seriously, though, what is it? Philanthropix? Ahh, well.

UPDATE: Okay, I'll fess up. I lifted this from Sarah.