A centauress (or whatever you call a female centaur).
Side story: A year ago, for my senior show at Southern Virginia University, I did an oil painting that included a female centaur (see image below). A visiting professor of Latin and Greek saw my painting and was very shocked at the idea of a female centaur. He told me that it went completely against the Greek notion of centaurs.
I am by no means an expert in centaurs or mythology, and I defer to his Harvard Ph.D. knowledge. But I would just like to point out that I’m not the first person to use the subject of a female centaur. While at the Musee Rodin in Paris, I saw this:
Somehow seeing Rodin’s centauress sculpture made me feel justified in making my own centauress artwork.