I thought of a pine sawyer, but there are no pine trees in that area, only cottonwoods. There is a cottonwood borer, but it has a distinctive black and white pattern.
One that looks close is the palo verde beetle. No palo verdes grow here in southern Colorado, but I read that their grubs will also bore into cottonwood roots. Maybe someone could save me a hard day's night of reading guidebooks and websites and identify it?
