According to the Centers for Disease Control and Prevention, the life cycle of the head louse has three stages: egg, nymph, and adult. Head lice eggs are called nits and are hard to see, often becoming confused with dandruff and dry hair spray flakes. The nits are found glued to the hair shaft very near the scalp. The eggs take approximately one week to hatch into a tiny nymph about the size of a pinhead. After three molts, the nymph will mature into an adult 7 days after hatching from the nit.
The life cycle of the body louse is the same as the head louse. They can be found on hair shafts anywhere on the human body but most often inside the seams of clothing. Adult body lice can feed on blood several times a day. The body louse will die within a couple of days without blood meals.
As with the head louse and body louse, the life cycle of the pubic louse consists of three stages: egg, nymph, and adult. Adult pubic lice are only found on human bodies and require blood to survive. The pubic lice are transmitted from person to person during sexual activity. Transmission can also take place from clothing or bedding to another human host.