As for the other part of your comment I felt the same way. I let it go, but really a caterpillar is not a young butterfly, the first day the butterfly is a butterfly it is a young butterfly. It is the same animal though. But a diferent form/stadium of it. If a young caterpillar is a butterfly it should be able to fly.
I think the maggots are a good example. Noone would call them flies.
(thinking about it I came up with this, hope it makes it clearer and not more confusing. It is like calling a one year old human an adult, just because at one point in his life he will be one does not mean he is one now)>
Or if you make it a fable/childrens story: the squirrel asked the butterfly how long he has been a butterfly. The butterflies' answer will be the number of days since he came out of his chrysalis. "This is my first day as a butterfly, before that I was a caterpillar"