The males have bright yellow wings with black borders. The forewings each have a dark round spot, while the hindwings have a lighter, orange spot. The females in the springtime generation are mostly yellow, while those in the fall generation are mainly white.
These butterflies have wingspans of 30 to 50 mm. Individuals in the springtime and fall generations tend to be smaller.
The green caterpillars have a white and pale pink stripe on both sides. The chrysalis is green with a yellow band and some black dots.