Woodies to the rescue - again!!!!

Seeing s it dull and dreary again all day today I decided to 'get in early' and get a blip in the bag before it was too late. 
After my success with the albino common rough woodlouse a few days ago I thought I would try the colony again, and this time I found this interesting little fella.
I think he is another Common rough woodlouse, but I am not at all sure why he is this odd 2 tone colour - maybe he is molting? I am hoping someone might be able to tell me.
Last day of term tomorrow - Yipeeeeeeeee