Bristle distribution along the wing margin of the small white cabbage butterfly, Pieris rapae (L.), was studied by examining the whole mount of the wing with a light microscope, after removing the scales around the bristles. The examination illustrated that the bristles in the forewing are distributed along its anterior and lateral margins, and those in the hindwing along its anterior, lateral, and posterior margins. All bristles are located in the ventral surfaces of the wings. The bristle distribution in the Pieris wing is compared with that of the microlepidopteran wings, and discussed in terms of wing movement.