Found this unusual moth whose behavior is very peculiar. Whenever startled, it darts under a leaf with wings folded like a Purple Duke. Perhaps our moth experts can help to ID this?
Richard
Noctuidae / Erebidae (depending upon your taxonomic bent!)
Catocalinae
Can't get further than that, as I only know of a couple of genera that have this sort of resting posture in HK, and your photo isn't of one of them! Nor does it help that so few species of moth are illustrated from the ventral view.
Richard - everything is relative. I'm still learning, even after 15 years moth recording, six of which were spent learning the HK fauna for my Ph.D. Trouble is, the more I find out, the less I think I really know