Initially i was just curious about their equipment, armour in particular, and asked the all-knowing Pompeus Magnus
After receiving his answer, however, it has become clear to me that those troops continued well into the late antique and even beyond. One of the major question is whether they were styled differently than the legions, i.e. whether they were armoured as heavily as their legionary counterparts? But, of course, that's just one of the possible questions about this interesting army regiments. So, everyone's invited to say a word or two and further the debate.