Which Georgia O'Keeffe painting series uses animal pelvic bones as abstract forms?

Georgia O'Keeffe's Pelvis Series uses animal pelvic bones as abstract forms. She began making these works in the 1940s, transforming bones found in the New Mexico landscape into subjects for color, space, and structure.

The pelvic bones interested O'Keeffe because their openings could frame the sky and distant landscape. Rather than treating them only as remains or symbols of death, she explored their curves, holes, and strong contours as formal elements. The series often places a bone against a vivid blue sky.

O'Keeffe had already painted animal skulls and other desert objects, but the pelvis pictures form a distinct group. Their simplified shapes continue her long practice of enlarging or isolating natural forms so viewers notice their abstract qualities.

The series is sometimes grouped loosely with her skull paintings, which can cause confusion. A pelvis is a different anatomical form, and O'Keeffe's titles often identify the specific bone or object. The works also show how closely her New Mexico environment and modernist experiments were connected.