We're going to try a butterfly kit this spring! A friend who homeschools her preschooler son has done this and they loved it.
Update on the butterfly kit: it was a very interesting experience. A little traumatic for me when one of the butterflies was caught up and struggling in getting out of the chrysalis and ended up not making it. I blame myself for not removing enough of the stringy fibers around the chrysalis when transferring to the net container. Lessons learned through experience. I would approve of repeating the experience, the kids would love to do it again also.