Bugs!!!

[wesleysgirl]

Weeks ago, we found an American Dagger Moth caterpillar ( someone else's photo ) in the yard. My son has a cool little bug house thing where you can observe insects, there's nice air holes etc, so we put it in there so we could watch it for a little while. We went to bed, intending to let the caterpillar go the next morning, but when we got up it had made a cocoon.

Does anyone know how long it takes a caterpillar in a cocoon to turn into a moth? It's been at least three weeks and no sign of anything from the outside...