A head louse is an insect of two to four millimeters. It is preferably between the head hair of man and takes the color of the hair.
Separated from their host they stay 48 to 55 hours alife. An adult louse lives thirty to fifty days. Female lice lay each day five to nine eggs or nits.
They look like a barrel of less than one millimeter in size. They're really stuck firmly to the hair near the scalp. After six to nine days there come nymphs, that are mini immature lice. These are mature after seven to ten days and will then lay eggs again.

Lice bite to suck blood. In addition, they give saliva, causing blood clots less likely. The allergic reaction to the saliva causes itching. That reaction does not start right away, but sometimes is coming weeks after an initial infection.

Lice walk. They can go to a new guest through clothing, a hug, a comb.

Remedies for lice
Comb the hair from back to front with a nit comb to the scalp. To soak off nits you can use
vinegar (water, sometimes tobacco is also added)
conditioner
lavender and coconut oil are quite often recommended
two tablespoons salad oil with a spoon petroleum (preferably odorless.) The oil soaks the lice eggs off and petroleum kills lice and nits.
Rub this mixture into the scalp and hair and cover with a solid towel. Let it all soak (one hour, possibly overnight).
Then thoroughly wash and comb.
A shampoo of nettle juice and water (50/50) would also help.
Dried crushed seeds of the spindle (Euonymus) as an insecticide would work against lice.

The lice hood is a large swimming cap with a funnel opening at the top, which fits well to the face on the head. Pour in a liter of olive oil or sunflower oil and let it soak for ten minutes. Then thoroughly comb the hair and wash well. After nine days you better repeat this so that all lice and their eggs are gone.

Starlings and others birds use ant to fight lice. They comb with the ant in the beak through the feathers, or sunbathe on an ant high. The irritated animals spray formic acid, and flea and lice go on the run. If you know any other solution...

Lice sit and stay on your head (hair). Not in hats or bedding. But it gives us a nice feeling if we treat them too.
Wash hats, scarves, headbands, bedding (especially pillowcases), stuffed toys in hot water (60°).
Or at least 30 minutes in the dryer that kills lice by overheating.
Or 24 hours in a freezer to freeze the lice dead.
Or two days (or longer) in a sealed bag, then all the lice die of starvation.

In tropical regions, clothing is also placed near an anthill. The ants eat the lice and nits.

"Lice contempt a bald head." (Marcel Marien)