The Lifecycle of Butterflies (1st) Students, after listening to fictional and non-fictional literature about caterpillars, and observing caterpillars from egg to butterfly, write a "biography" of a caterpillar using appropriate vocabulary and time lines.
http://www.amazon.com/exec/obidos/ASIN/0399208534/atozteachstuff/102-8917665-5952859
A lesson in Symmetry (2-4) Students discover that butterflies look identical on both sides. This project teaches them the meaning of symmetry as they create their own "balancing butterfly." Includes questions to encourage students to think about other symmetric objects they can name.
http://www.smm.org/sln/tf/s/symmetry/symmetry.html
Fun Facts about Butterflies (5th) This site contains several printable fun fact sheets on butterflies. These can easily be incorporated into a butterfly unit.
http://www.butterflyhouse.org/