September 24. When they're eating and growing, caterpillars are perfectly happy to stay in one place as long as you keep bringing them new food. But when it's time to start making a chrysalis, they like to wander. Today one of our caterpillars spent hours crawling around its box. It finally decided the screen on top was where it wanted to hunker down. It spun silk to hold itself in place. Several hours later the caterpillar shed its last skin, leaving this chrysalis.