LOUSE, SEM. LOUSE, SEM The louse is a small wingless insect with a flat body measuring about 2 to 3 mm. The head louse is one of three species which parasite humans. Lice feed on human blood and leave tiny red spots on the skin where they sucked blood. These spots are itchy and lead to scratching lesions. The female louse lays about 10 white eggs a day which hang on body hair until hatching. Lice are transmitted from person to person by direct contact or via clothes. Lice infestation is an im