Human Head Louse (Egg/Nit)

Scientific Name: Pediculus humanus capitis

Order & Family: Order: Psocodea; Family: Pediculidae

Size: Nits (eggs) are approximately 0.8 mm by 0.3 mm; adults are 2-3 mm.

Human Head Louse (Egg/Nit)

Natural Habitat

Human scalp and hair, specifically attached to hair shafts close to the scalp.

Diet & Feeding

Obligate parasites that feed exclusively on human blood several times a day.

Behavior Patterns

They cannot fly or jump; they move by crawling. Eggs are cemented to hair shafts and hatch in 6-9 days. They are highly contagious through direct head-to-head contact.

Risks & Benefits

Causes intense itching and scalp irritation. They do not transmit diseases, but scratching can lead to secondary bacterial skin infections. They offer no ecological benefits to humans.

Identified on: 5/15/2026