Dendroides fire-colored beetle,
Illlinois
We in the Friday Beetle Department don’t often turn our attention to immature beetles. But these Dendroides larvae are too striking to pass up.
Dendroides fire-colored beetles inhabit the flat, two-dimensional space under the bark of dead trees. The oddly compressed body helps this insect squeeze through tight spaces looking for food.

update: Identification updated, on closer examination of the urogomphi. I think everyone should spend more time examining urogomphi.
Photo details: Canon mp-e 65mm 1-5x macro lens on a Canon EOS 50D
ISO 100, f13, 1/250 sec, diffused flash