I posted this on bugguide.net and some people think this is a Xylophagus lugens. Size was between 25 and 30mm. Found resting on tree bark in a oak forest. Northern Illinois, USA. Any thoughts?
I've little doubt this is in Xylophagidae.
But it's NEw world (see disclaimer in my profile)\
Suggestion: ask Martin Hauser (Illinois in the past, now in California)