Head Louse (Eggs/Nits)

Scientific Name: Pediculus humanus capitis

Order & Family: Order: Psocodea (formerly Phthiraptera), Family: Pediculidae

Size: Nits are approximately 0.8 mm long; adults are 2-3 mm long.

Head Louse (Eggs/Nits)

Natural Habitat

Human scalp and hair, specifically attached to hair shafts near the scalp for warmth.

Diet & Feeding

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

Behavior Patterns

They do not fly or jump; they move by crawling. Eggs (nits) are cemented to the hair shaft. They cannot survive more than 24-48 hours off a human host.

Risks & Benefits

Cause intense itching and possible secondary skin infections from scratching. They are not known to spread disease but are a significant public health nuisance.

Identified on: 5/13/2026