Soon, the larva will be ready to pupate. As do most brush-foot butterflies, the Painted Lady is one that will find a spot usually a distance away from its host plant, upon which to pupate (so as to deter predators, more than likely).
A silken button will be made and the caterpillar will suspend from its last prolegs in a 'j' position with its head hanging downward. It can take upwards of 24-hours for this final larval molt. You will probably find a little black blob either attached to the chrysalis or on the ground nearby. This is the remaining exuvia…the final 'molt' from the caterpillar stage. It will include the head capsule of the caterpillar. It is rather cool to look at under a magnifying lens!
The chrysalis or pupa (NOT a cocoon!) is a non-descript brownish or tan colour with gold flecks. Close inspection and you can spot the spiracles and other features of the soon-to-be butterfly.
OH, you should be forewarned that the pupa of the Vanessa cardui does have a rather unique characteristic that is not to frighten you. It is intended to scare PREDATORS but is often a shock the first time it is observed. When you least expect it, the pupa may start doing a very strange rapid jiggly dance. I mean, a quick and fast rat-a-tat-tat that will make you wonder if it is going to fall from its perch! Don't worry…it won't fall.