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Life Cycle of the Head Louse

There are three life stages for lice: the egg (also called a nit), the nymph, and the adult.

Life Cycle

Egg/Nit

Nits are very small, about the size of a knot in threat.  Nits are laid by the adult female at the base of the hair shaft nearest the scalp.  They are firmly attached to their hair shaft.  They are amber to chocolate-brown when ready to hatch and yellow to white when empty. 

Nymph

Nits take about 1 week to hatch into a baby louse, called a nymph.  Nymphs mature into adults about 7 days after hatching.

Adult

The adult louse is about the size of a sesame seed, has six legs, and is tan to grayish-white.