Chameleon moth

Large purple moth
Moth from above
Large brown moth
Moth from behind

I have known for a while that the apparent colour of butterflies and (I assumed) moths could change quite dramatically according to viewing angle. My favourite examples of it were the Common Eggfly – (1) and (2) – and its cousin the Blue-banded Eggfly. But then I turned over a board and found this moth – yes, the two pictures show the same moth on the same board under the same lighting.

From above, gorgeously patterned purples, blues and blacks, and from behind, a pleasant but dull red-brown: my new favourite example of the phenomenon.

It’s not really a ‘Chameleon Moth’, by the way. That was just what I called it while I was finding out the correct name (thanks again, Graeme), Speiredonia mutabilis, but the real name does mean something similar – ‘mutabilis’ is, roughly, ‘changeable.’ It doesn’t appear to have a genuine common name.