After several years to reflect on the matter I have decided that I must have mixed up larvae and that no way is this the larva of Centron*opus cal*caratus. They had been associated with this life cycle series. Here's what I wrote at the time:

I collected two of these decent-sized larvae and kept them in a container with some frass/duff from beneath the bark of a pine log that Tom Murray and I scalped bark from on March 18, 2006. Doesn't this look like a ceram*bycid larva to you? Wouldn't you expect a nice longhorned beetle to mature from it? That's what I thought too. I thought I knew my larvae...