While I can't identify the species, I can provide some insight. It's a beetle larva of the order Coleoptera. Larvae of this group are characterized by a white "grub"-like body with a hardened, dark head. To identify the specific species, you would need to find an entomologist to give a specimen to (they would likely ask the species of wood and how long ago the tree was cut down too). General firewood insect information: http://putnam.cce.cornell.edu/resources/insects-and-firewood-some-facts

Well, I also can't find the name of it but I love gardening and I also find many kinds of insects. I usually post my images on google and check. Sometimes I can find a nice answer.