Light Emerald

Light Emerald moth, Campaea margaritata.  Flew across Saville Row on the morning of 20 July 2011.

This moth flew across my path in the early morning and landed on a laurel leaf, where it rested while I photographed it with my Ixus 100, staying put even though I put my hand right next to it to pull a leaf out of the way. Aha, I thought. I have the books now, so I should be able to identify this one without assistance.

I wasn't sure I could, though. I can see the signs of my inexperience. I have failed to identify several moths that I have good clear photos of.

When I was writing machine code for the ZX Spectrum, if a sequence failed to work as expected it was very tempting to say that there was an error in the manual, or an undocumented effect. But there never was. It was always an error in my code or my understanding of it. In the same way, it is tempting to say that all those moths I can't identify must be micromoths, and therefore not in my book, which doesn't cover those. And some of them might be, but I am pretty sure that others are actually in there somewhere, as yet unrecognised by me.

I thought I recognised this one as one of the "Waves" but when I looked them up, the banding on their wings was darker than the background, not lighter. But on the same page was a Light Emerald.  This moth does have a slight greenish tint, which I thought at first was because of the green leaves it is resting among. The Light Emerald's description says "fading to whitish" and as this specimen is damaged, it could well be old. And the Light Emerald, I suddenly realised, has one fewer wing band than the Waves, and so does my specimen.

The diagram in my book, the widely used "Concise Guide to the Moths of Great Britain and Northern Ireland," shows the Light Emerald's bands as having both a light and a dark component. My specimen does not show that.  The lower band on the forewing should match up with the single band on the hindwing.  On this one, it does not. And the description on the UKmoths site mentions a blood-red tip to the forewing, which mine does not seem to have either. But moths do vary a lot; the experts say they haven't read the books.

I could still be wrong, of course. I don't yet now which features are critical and don't change, and which are mutable, either generally or with age. Moths are tricky.