Photobombed!...

...A backblip.

I had crept closer and closer to the brimstone, and through the lens, recognised in a split second that it's posture changed! It saw the photobomber before I did. Both were gone in an instant.

I might have mentioned before that I had a biology teacher who was an expert on butterflies... (I used to listen a bit, but how I wish I had listened more. He was a Star. I do hope he's still 'at it').

Backblipping.