There has long been an urban myth that it is against the law to kill a praying mantis. This probably comes from the fact that they kill pest insects and are considered benificial.
When I was kid, my best (?) friend placed a praying mantis under a large clam shell with out me knowing it. Then bet me I could not break the shell with the heel of my shoe. After seeing the smashed shell with bug guts underneath, my friend spent the next week telling every grown up he met I had killed a mantis - hoping someone would call the police.
A childhood belief about creepy crawlies

others believed things like this
- As a child I thought that if you killed a praying mantis, you had to pay God $50.00.— stevie p
- I used to think that the praying mantis was related to the katydid!Anon
- I also used to think if you stared at a mantis you would be paralyzed forever.
— inma d - I once for some reason thought a Mantis was a bird, instead of a bug...— Laurie J.
- I used to believe that the sky is just a very thin blue egg shell— Alan
- I used to think shell macaroni was sea shells.— Don Northrup