Yesterday was day 3 for my little caterpillar. I didn't take a picture, because it was too late, and too windy for a teeny tiny close-up. This morning I checked on it bright and early, and was pleased to see that my little caterpillar appeared to be shedding its skin.
The little black thing you see is the exoskeleton of the head.
Unfortunately, something went wrong. Hours passed and the moult had failed to progress. He was dead in his old skin.
So this caterpillar diary has come to a sad and sudden end. Nature is tough sometimes.