3rd to 4th instar. The caterpillar has walked out of its old, too tight skin. After a short break for a rest, it turned round and ate the skin.
At the top of the image the silken threads which make up the cocoon are visible and are pulling the sides of the Buddleia leaf togther. The caterpillar is bent backwards and a silk thread is visible from the centre left of the leaf to the spinarette below its head. It will attach that thread to the right of the leaf.
The top of the cocoon has been built, a dense thicket of silk and in this shot the caterpillar is beginning to drag the leaf into place. Most of the leaf is in position now.
Job done! The bottom of the leaf has been pulled up and attached to the silk which joins the 2 sides of the leaf. The caterpillar is still slightly visible but soon the chrysalis will be formed enclosing the caterpillar so that the miracle of metamorhosis can occur. The cocoon is now in the coolest part of the house and will be kept safe until the moth ecloses.
180625 Mullein @bcyorkshire.bsky.social @savebutterflies.bsky.social #mothsmatter #muchadoaboutmothing #gardenmothscheme #teammoth #york #uknaturalists #insectphotography I've never seen a caterpillar build a cocoon in such detail before, it's an incredible process which took about 24 hours