You can try the glass jar tilted at an angle with the lip next to its rock, and food/bait at the bottom. I've tried putting Saran wrap over most of the mouth of a jar to keep fish out. You can also check out commercial plastic mantis traps (I think that someone makes one, but I'm not sure). Regardless, good luck - they are quite intelligent! You could also literally feed it like a pet, and over time as it gets to trust you, lead it to a glass jar trap.
Don't put your fingers anywhere near it!