What do lice look like on a human? - briefly
Lice are tiny, wing‑less insects about 2–4 mm long, with a flattened, oval body that ranges from gray‑white to brownish‑tan and a six‑legged, crab‑like appearance. They cling to hair shafts near the scalp, and their eggs (nits) appear as tiny, cement‑bound, oval shells attached close to the skin.
What do lice look like on a human? - in detail
Human head lice are tiny, wingless insects measuring 2–4 mm in length. Their bodies are laterally flattened, allowing them to move easily through hair shafts. The head is broader than the thorax, giving a somewhat teardrop shape when viewed from the side. Color ranges from pale gray to brown, often appearing translucent until the insect feeds and its abdomen fills with blood, turning a darker reddish‑brown.
Key visual characteristics include:
- Six legs: each leg ends in a claw‑like hook that grasps hair strands. The claws are short, curved, and spaced widely, providing a secure grip.
- Antennae: three-segmented, about 0.5 mm long, positioned near the head’s front; they are slender and often difficult to see without magnification.
- Eyes: tiny, dark spots located on the sides of the head, not easily observable without a microscope.
- Mouthparts: piercing‑sucking apparatus located at the front, used to draw blood from the scalp; the proboscis is concealed when the louse is at rest.
- Body segmentation: a distinct head, thorax, and abdomen; the abdomen is segmented into nine visible sections, each bearing tiny bristles (setae) that can be seen under magnification.
When a louse feeds, its abdomen expands, creating a noticeable bulge that can be seen as a small, rounded bump on the scalp. After feeding, the insect may appear darker and more opaque. Nymphs, the immature stages, resemble adults but are half the size and lighter in color, lacking fully developed eyes and antennae.
Eggs (nits) are oval, about 0.8 mm long, and firmly attached to hair shafts near the scalp. They are white or yellowish and often mistaken for dandruff; unlike lice, they cannot move and remain glued at an angle of roughly 30–45 degrees to the hair.
The combination of size, flattened body, hooked claws, and color change after feeding provides a reliable set of visual cues for identifying these parasites on a person’s head.