Hatch will depend upon the temperatures. Egg cases will typically become active after 2 to 4 weeks of temperatures over 75 degrees. In some climates, or during some cool springs, that may not occur until later on in the summer.

My suggestion to your Dad is "be patient, grasshopper". ;-)

I don't know about hatching outside, but it takes about 8 days to hatch in a Scots Pine Christmas tree, fully decorated. LOL!

Ha! I am SOOOO glad that you mentioned that! When I brought up that exact scenerio in a different forum, many people refused to believe that such a thing ever happens.

Makes for some entertainment during the holidays, doesn't it?

Talking about entertainment....
My wife was so worried that the praying mantis gang had nothing to eat, and it was too cold outside, etc. The next day, we noticed a large dark spot on the living room ceiling, and when I went to investigate, It was a group of spiders!!! That tree was a veritble ZOO!
BIll