I found this species on the muddy ground along the small river. They sucked water from the mud. The color and patterns of underside is very simple and they fly slowly, so nobody is attracted by this species.
They have wet and dry season forms depending on the active season like as another butterflies living in Hong Kong. The inserted photo seems to be the dry season form, although the pattern differences are very small between dry/wet season forms.

[Distribution]  throughout the south-east Asian region