Which Georgia O'Keeffe painting series centers on a red-and-yellow pelvic bone?

Georgia O'Keeffe's Pelvis Series centers on paintings of pelvic bones, including red-and-yellow compositions.

O'Keeffe began painting bones after finding animal remains in the New Mexico desert. She treated the bones as sculptural forms, using their openings to frame sky, light, and distant landscape rather than presenting them simply as anatomical objects.

The series demonstrates her ability to transform ordinary desert discoveries into abstract images. Works from the group include Pelvis Series, Red with Yellow, painted in 1945, and Pelvis IV, painted in 1944.

The bones in these paintings are not human remains. They are animal bones, and their recurring shapes connect O'Keeffe's New Mexico paintings with her earlier interest in enlarged, isolated forms.