[header] How to make a pitfall for catching insects [title] Dig a small hole in or near your garden. [step] If you have noticed signs of tiny animal or insect activity in a certain place, that might be the best spot to place your pitfall. [title] Cover the sides of your cup or other container. 
[step] Use cling film or vegetable oil to coat the container before setting it into the hole. This makes it slippery, so that the quarry cannot escape once trapped.