What do house lice look like? - briefly
House lice are tiny, wingless insects about 2–3 mm long, with a flattened, elongated body that is gray‑brown and covered in fine hairs. Their heads are small, bearing short antennae and chewing mouthparts.
What do house lice look like? - in detail
Domestic head lice are small, wing‑less insects that cling to human hair. Adult specimens measure 2–4 mm in length; females are slightly larger than males. The body is flattened laterally, facilitating movement between hair shafts. Color ranges from gray‑white to light brown, becoming darker after a blood meal.
Key morphological features include:
- A head that is wider than the thorax, bearing six short, backward‑pointing antennae each about 0.3 mm long.
- Compound eyes positioned on the sides of the head, providing a broad field of vision.
- Mouthparts adapted for piercing skin and sucking blood, located at the front of the head.
- Three pairs of legs, each ending in a single claw that grasps hair shafts with strong, hooked tarsi.
- Six abdominal segments covered with fine, overlapping plates called tergites; the posterior segments end in a pointed abdomen.
Nymphal stages resemble adults but are smaller (1–2 mm) and lack fully developed reproductive organs. They progress through three instars, each molt increasing size and darkening coloration.
Eggs, or nits, are oval, about 0.8 mm long, and firmly attached to the base of hair shafts by a cement‑like substance. They appear white or yellowish until hatching, after which the emerging nymph begins feeding within hours.