Unless the beetle has something which easily distinguishes it from others it will be difficult if not impossible, even experts with a specimen under a microscope will have trouble with some due to interpretation. Some depend on small detail such as how many ridges there are in the elytra or how many puncture holes it has in certain places.
Some can be identified by the number of segments in the antennae, or colour of them. Or the shape of the pronotum, whether or not it has rounded or sharp corners, the surface structure of it etc.
http://theearlybirder.com/inse...
http://www.americaninsects.net...
http://bugguide.net/node/view/...
Watch them and think how much they are enjoying their short lives while you provide one of nature's creatures with something which they can benefit from, and in turn will likely benefit another of nature's creatures.
