Here's what we did today. We began by reading Ten Little Ladybugs. We weren't making ladybugs, but I didn't have a specific book about caterpillars or butterflies (I need to do something about that) :-) and this book has beautiful pictures of caterpillars and butterflies.
First we made a bouncypillar. I got the idea here. You just fold two strips together to make a boingy body and then add a face, antennae (we used paper because I didn't know if little hands would be able to glue pipe cleaners in there) and of course, googly eyes.
Then we moved onto a clothespin butterfly/caterpillar. The base is a clothespin, the wings are 1/4 of a paper towel. The kids decorated the wings with markers and crayons. Then they chose their body and eye colors (colored googly eyes!!! Love them!). We then added the antennae with a fun pipe cleaner. The wings are clipped into the clothespin so you can take them out to make a caterpillar and add them back in to make a butterfly. I thought these would be fun with a magnet on the back and one little cutie in my class said she was going to use it as a bookmark.