Or is it a regional thing? I know that it was something that I heard many times when I was a wee child. "Don't you ever kill a praying mantis! The cops will find you and throw you in jail!" The crime was accompanied by a fine anywhere from $50 to $1,000 or so. It's something that everyone I have ever asked also "knew" about.
But here's the thing. There is no law against killing them. There has never been a law against killing them. I don't know how that rumor started. Maybe it's because they are an attractive and beneficial insect. Some organic farmers use them as a form of pest control, but they will eat pests along with other beneficial insects as well so I don't know how well that works. But, regardless of their use, they aren't a pest. They don't destroy crops. And they are kinda noble looking.
So maybe farmers told their kids a long time ago that it was illegal to kill a praying mantis. Or maybe it was a religious thing. Some cultures revere the praying mantis. Whatever it was, the insecticide rumor was passed down from generation to generation. I remember hearing about it vividly. I even remember a friend of mine from the neighborhood capturing one and telling him that he better release him because the cops were gonna put him in jail if it died. I think I scared that dude straight because he let it go.
Is this something you heard about when you were a kid? Or is it just a regional Northeast thing? Inquiring minds and all.