I think just black...all the pics I've seen were black. I had an escaped superworm pupate and the resulting beetle was eaten by my rosie. Is darkling beetle the correct name for the adult stage of zoophoba morio?
From what I've seen in my culture and other peoples is that they seem to start out a sort of brownish orange and then over time they turn black....I love giving them to my Bane (a Northern Bluetongue skink)......he loves the "CRUNCH!!!":}
When zoophobas molt into adult beetles they start out white, turning orange, then burgandy, and finally dark brown or black when fully sclerotized(hardened). Almost all adult beetles in the family Tenebrionidae which includes mealworms and superworms are called "darkling beetles".