Nearly all of the mites were connected in some way with the Victorian 
immune system, and of these, most were immunocules whose job was to drift 
around the dirty littoral of New Chusan using lidar to home in on any other 
mites that might disobey Protocol. Finding one, they killed the invader by 
grabbing onto it and not letting go. The Victorian system used Darwinian 
techniques to create killers adapted to their prey, which was elegant and 
effective but led to the creation of killers that were simply too bizarre to 
have been thought up by humans, just as humans designing a world never would 
have thought up the naked mole rat. Dr. X took time out to zoom in on an 
especially freakish killer locked in a death-grip
around an unlabeled mite. This did not necessarily mean that Hackworth's flesh 
had been invaded, rather that the dead mites had become part of the dust on a 
table somewhere and been ground into his skin when he touched it.