Nit comb. This comb is used for removing headlice from hair. Head lice (Pediculus humanus capitis) are small, wingless insects that suck blood from the scalp of humans and lay eggs (nits) on hairs. The lice leave bites that cause itching of the scalp. This comb is used on hair after conditioner has been applied. It has closely-spaced spiral-etched teeth which trap adult lice and their eggs.