Black on yellow

The butterfly Euploea core is called the Common Crow. In Australia, it occurs mainly in warm coastal environments. It is also found in southern Asia. 

There are very many species of Crow butterfly, which are given that name because many are predominantly black in colour. Personally, I think it a shame that such an attractive little creature doesn't have a more attractive name.

This one was feeding on a Silver Ragwort plant in a neighbour's garden.