This group once was considered a subgenus, given the names Piccarda and Cathaemia. However, the term 'subgenus' has become increasingly unpopular with entomologists.
You can therefore see that this group is particularly distinct from the others. Whilst it has the usual Delias structure, it differs by way of pattern and genitalia. including scent-scale.
The distinguishing pattern of the group is that the underside hind wing has a submarginal band of red spots and no red subbasal stripe. The markings usually being within a black border. To be certain of correct grouping, however, the scent-scale and genitalia need to be inspected, as they are quite different from the other groups.
The group has a very wide distribution, ranging from India through to Taiwan, China, Australia, Indonesia, Malaysia and the Philippines.