Human Head Louse (Egg/Nit Shell)

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.

Human Head Louse (Egg/Nit Shell)

Natural Habitat

Found exclusively on the human scalp, typically attaching eggs (nits) to hair shafts close to the scalp for warmth.

Diet & Feeding

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

Behavior Patterns

Lice cannot jump or fly; they move by crawling. Eggs are glued to hair with a specialized cement. They undergo incomplete metamorphosis (egg, nymph, adult).

Risks & Benefits

Causes intense itching (pediculosis) and scalp irritation due to an allergic reaction to saliva. While a nuisance and highly contagious through head-to-head contact, they do not transmit diseases.

Identified on: 1/2/2026