It depends where you are. Usually, the beetles and larvae can be found in generally untouched areas of deciduous forests. I've only ever found 1 larvae in the area I live in, but certain friends of mine from more deep country places have found some adults and larvae. To find the larvae, you can try check under deciduous tree logs that have gone through decomposition for some time (the wood feels mushy and easy to break apart) but wear some sort of protective gloves and long-sleeved clothing so you don't get any bites, scratches, punctures, or poisons from unwanted guests. I've heard adults can be attracted with some strong-smelling sugary substance (generally with lower acidity) in a jar lid or slightly open container, or by shining a large blacklight on a white bedsheet during the night may produce some results. As I have said, you need to have a very human-free environment to do these things, as the fungi that grows on dead wood may require a highly pollutant-free environment (not always the case but it needs to be somewhat clean) which the larvae particularly favor and thrive on.