The caterpillars that were eating the sunflower leaves have hatched. When we came home for lunch yesterday one of them was climbing the jar, anxious to get out. Because we had been gone for hours, I did not want to stress him any further and hastened to let him out of the jar (no pictures).
But we knew it would not be long before the other cocoon would pop, so we have been more vigilant this morning, and lo and behold, I just caught another new butterfly flexing his wings in the jar. This time we were able to get some pictures of Chlosyne lacinia, still in the jar, and climbing out.