Found 2 big fat bagworms

Wonder where these are from, when most of them have been pretty small.

Unless without competition, they just grew fast.

I wonder at this date, whether they could reproduce right away?

According to this info, males would need to hatch and fly around to fertilize the females, usually end of August.

In late summer, around mid-August, bagworms pupate inside the cases. It takes about 7 to 10 days for bagworms to change from pupa to adult, depending on the temperature. The males are ugly, black moths with clear wings, emerging through the bottom of the bag. Males fly off to mate with females. Females never develop into winged moths and lack eyes, wings, legs, and antennae; they remain inside the bag made during the larval stage, producing eggs before dying. The eggs are the overwintering stage. There is one generation a year in Illinois.
http://hyg.ipm.illinois.edu/pastpest/200309c.html