Head lice eggs are about half an inch long. The adult louse is between two and three millimetres long, and the nymph is about one millimetre. Lice live for about 30 days on the head before they die. Their life cycle can be complicated, but fortunately, there are a number of steps you can take to get rid of the infestation.
First, make sure you understand what a head louse is. Lice are tiny, wingless insects that live in the hair and feed on the scalp. These tiny parasites have six legs and can camouflage to match your hair color. Once they hatch from an egg, they change into nymphs and eventually become adult lice. Adult lice are two to three millimeters long and are unable to jump or fly.
Lice eggs can be spotted in several ways. Most people notice them as nits on the scalp. However, some parents prefer to refer to them as nits. Nits are actually the empty shells of head louse eggs that are attached to the scalp. When the eggs hatch, they are pale white or brown and look like dandruff.
Lice eggs hatch after a week and the nymphs emerge two to three days later. These louse nymphs become adult louse in nine to twelve days and the life cycle of a head louse repeats every three weeks. Adult lice are two to three millimeters long, about the size of a sesame seed.