Head lice are parasites (about the size of a small ant) that often develop in the hair of children and sometimes adults.

The head louse, Pediculus capitis humanus, is by no means a new nuisance. The insect has been an unwelcome companion to humans, probably from the beginning, as with its close relatives, the body louse and the pubic (or crab) louse. Head lice infestations seem to be on the rise in recent years - as almost any parent of an elementry-age child can tell you. A parent's first...