Olga checks a pitfall trap. Photo courtesy of Margaret Thayer.
Pitfall traps are successful in catching insects that crawl along the ground.
Ground beetles are often found in pitfall traps. Find a plastic container with a lid, such as an empty margarine tub. Dig a hole in the ground the same size as the container. Put the container inside the hole, but be sure the top of the container is even with the ground. Insects walking along the ground fall into your trap and have a hard time escaping.