So as I was just about to leave for a 5 day conference in November, I ran home from work to my kitchen to find:
literally hundreds of praying mantises, smaller than a fingernail, mostly in the kitchen but already quite distributed through the lower floor of the house.
A friend had given us an egg case in the late summer that we has absent-mindedly left in the kitchen.
This photo was taken last week (2 months after hatch), when there were two still alive and well (they eat cat food).
Two days ago this one ate his sib, now there's only one.