They are the kind of lice which make their home in your hair. The adult louse is a greyish-brown wingless insect which bites the scalp and sucks blood. The female lice attach their eggs, or “nits“ to the hair shaft close to the scalp and then hatch in 7 to 9 days, and within 3 weeks, are fully grown and able to lay their own eggs. Lice live for 3-4 weeks and the female can lay up to 10 eggs a day.