I wonder if the fluffy mass on the other side of the same leaf contains eggs laid by this moth. A similar mass found in the same area last year contained many brownish eggs
I think Trichiocercus sparshalli is more likely, the females of which have the brown and black thorax, and the hairy gold tail, like this specimen. But the white moths of Lymantriidae and Notodontidae are very hard to distinguish just from photos. Can you take the egg mass home for protection, and rear it for identification of the resulting larvae and moths, and then take all the specimens you successfully rear back for release at the same spot?
This is a female Lymantiinae rather than Trichiocercus. CNM has them under Acyphas semiochaea, Acyphas chionotis and Lymantiinae sp, and as Don has pointed out on one of the records there are other possibilities.