Caterpillar Investigation, Part 2

Yesterday, I posted about the caterpillars that appeared on our parsley a little over a week ago. I also told you I'd provide updates regarding any changes.

Here's a quick photo update.
Taken the first day we officially observed them- last Wednesday, September 22nd. This was the largest caterpillar at the time.

Taken two days later on, September 24th.
And here' s one taken today, September 27th:
My how they've grown in just 5 days! Nearly doubled in size!

Our primary question is: Will the caterpillars change into butterflies? And, if they do, how long will the process take? My daughter has already connected our observations to The Very Hungry Caterpillar by Eric Carle. In it, a fictional caterpillar eats lots of food (not all of it "real" caterpillar food) and then changes into a beautiful butterfly.

What do you think will happen? What questions do you have?