Earlier this year I planted a couple of milk weed plants in my front yard. This is the Monarch butterfly's favorite plant, both for the flowers and for their caterpillars to feed on the leaves. I've had a few of the caterpillars on the plants, but kept on disappearing, possibly to predators, so I built a protective cover made of fabric screening material, a couple of old metal window screens, and some PVC pipe. It's not pretty, but it works. The pics show the overall contraption, and then a closeup of one of the caterpillars inside, and then also a chrysalis that a caterpillar has just formed in the past 2 days as it metamorphosizes into an adult Monarch butterfly.