There actually is a really interesting bit of history to be found in the three lice that live on humans (head lice, body lice, and pubic lice). An excerpt from a story covering the genetic relationships between human lice and other primate lice:
“Lice are intimately adapted to their hosts and cannot long survive away from the body’s blood and warmth. If their host evolves into two species, the lice will do likewise. So biologists have long been puzzled over the fact that the human head louse is a sister species to the chimpanzee louse, but the pubic louse is closely related to the gorilla louse.”
A fascinating article about nakedness, clothes, evolution, and possible interspecies sex.