I watched the beetle to figure out how it made the noise and it appears as though it makes it by puffing out its abdomen and then sucking it back in, rubbing the top of it against its wings as it does to make a scratchy noise. Pretty wild.
Ecological notes: Males have very robust enlarged feathers on their antennae for picking up whifs of the female pheromones. This one, with much smaller antennae was most certainly a female. Most of the beetle's life cycle is spent underground as large white larvae with yellowish to orange heads - hard to miss. The females lay their eggs in the soil, which makes me wonder if the defensive posturing of the female was her actually defending her egg-laying territory from an intruder (me).
Where: My backyard (maybe yours too?)
Other notes: Heard my first cicada of the year today!