One of my students confessed to having killed a praying mantis when she was young-- and she referred to this bug-slaughter as "committing a felony"-- and I can remember hearing the same thing when I was a kid: that it is against the law to kill a praying mantis, but according to the myth-busting website snopes.com, this is an urban legend . . . so if one of those large green alien-headed critters surprises you while you're on the john and you smash it with a magazine, you don't have to chop the body into little pieces and sneak it down to the Pine Barrens for a a clandestine burial.