cecropias- double brood?

[Sheena]

Hi,
I am raising cecropias, it is the middle of July and already I have some in
the 5th instar. They seem to be growing faster than normal. At the rate they
are going, the larger ones will be making cocoons soon. If they make cocoons
so early, is there a possibility of a double brood, and if so, what will
happen? I live in Minnesota, so I'm not sure what would happen if there is a
double brood. I have never heard of this before with cecropias. Maybe there
won't be though. Can anyone help me?