Pieris rapae crucivora
The upperside is creamy white with black tips to the forewings. Females also have two black spots in the center of the forewings. Its underwings are yellowish with black speckles. It is sometimes mistaken for a moth due to its plain-looking appearance. The wingspan of adults is roughly 32–47 mm (1.25–2 in).
It is widespread and populations are found across Europe, North Africa, Asia, and Great Britain. It has also been accidentally introduced to North America, Australia and New Zealand where it is causes damage to cultivated cabbages and other mustard family crops.
I spotted this in Phu Hin Rong Kla National Park. It was difficult to photograph and this was the best shot I could get. It's resting on Sensitive plant, Mimosa pudica. One of the least colorful butterflies I saw in Thailand.