Hello - I understand that a lot of people like myself (total newbies to keeping beetles) dump larvae photos here, but I promise to use this as an opportunity to learn diagnostics!
I brought a piece of rotting wood into my home this winter to use as a landscaping feature in a desert Tenebrionid enclosure. While it was drying out, this larva exited and began crawling around. I put it into a container of moist millipede substrate with some extra chunks of wood. It immediately burrowed, found a chunk, and drilled into it. A couple weeks later out of curiosity I split the chunk, found it still living inside, and so added a couple more chunks and set it aside to see what might happen.
If anyone has any suggestions on ID, even genus or family, I'd be very grateful! I didn't get out the calipers, but my best estimate is that it's between 1/4-inches and 1/2-inches in total length. The flash on the camera brightened the body a bit. Under normal ambient light the body was more orange/less yellow, and the head was noticeably darker than these pictures with the bright flash might suggest.
Allegany County (Southwestern part of the state), NY (USA)