Human Head Louse (Egg/Nit)

Scientific Name: Pediculus humanus capitis

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

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

Human Head Louse (Egg/Nit)

Natural Habitat

Exclusively on the human scalp, attached to individual hair shafts near the skin surface.

Diet & Feeding

Obligate blood-feeders; they consume human blood multiple times a day.

Behavior Patterns

Nits are cemented to hair shafts with a waterproof glue-like substance. They cannot move. Once hatched, the lice crawl between hairs to stay close to the scalp for warmth and food.

Risks & Benefits

They do not transmit diseases but cause significant itching (pediculosis) and secondary infections from scratching. They provide no ecosystem benefits and are considered a nuisance parasite.

Identified on: 1/1/2026