Black patch in moth eye

[jamesk]

This moth has an irregularly shaped black patch in its right eye only, left eye does not have any. What are the possible reasons for this patch? Also if possible (really sorry, forgot to get proper overall diagnostic shots), ID of this moth for my records will be much appreciated, thanks!

http://farm5.static.flickr.com/4033/4711792957_bbe5ed19e2_o.jpg

http://farm5.static.flickr.com/4017/4712432722_bcd2e10350_o.jpg

[hkmoths]

Looks like Achaea serva (Erebidae, Erebinae); the black patch is the bases of the ommatidia that you are viewing (http://en.wikipedia.org/wiki/Ommatidium). The amount of the black you see depends upon your angle of view.

cheers,
Roger.

[jamesk]

Thank you, Roger!