What do lice and their eggs look like? - briefly
Adult head lice are small, wingless insects about 2–4 mm long, with a flattened, elongated body that ranges from gray‑white to brown and is covered in fine hairs. Their eggs, known as nits, are oval, roughly 0.8 mm in length, firmly glued to hair shafts near the scalp, and appear white or yellowish.
What do lice and their eggs look like? - in detail
Lice are small, wing‑less insects measuring 2–4 mm in length. Their bodies are laterally flattened, which facilitates movement through hair or clothing fibers. The head bears a pair of antennae, each composed of several segments, and compound eyes that are reduced or absent in some species. Mouthparts are adapted for piercing skin and sucking blood, appearing as elongated stylets. The thorax supports three pairs of legs, each ending in claws that grip individual hairs. The abdomen is segmented, often showing a light‑colored band near the posterior end. Color varies among species: head lice (Pediculus humanus capitis) are typically gray‑brown, while body lice (Pediculus humanus corporis) may appear slightly lighter; clothing lice (Pediculus humanus vestimenti) are similar in hue.
Eggs, commonly called nits, are oval, about 0.8 mm long and 0.3 mm wide. The shell is smooth, translucent to whitish, and slightly curved to match the contour of a hair shaft. A single egg is attached by a cement‑like secretion that hardens, creating a firm bond to the hair about 1 mm from the scalp. The attachment point is often visible as a tiny, glossy disc at the egg’s base. Internally, the egg contains a developing embryo with visible segmentation and, in later stages, a darkening embryo that can be seen through the shell. After approximately 7–10 days, the nymph hatches, leaving the empty shell attached to the hair.
Key visual distinctions:
- Size: adult lice 2–4 mm; nits <1 mm.
- Shape: lice have an elongated, dorsoventrally flattened body; nits are oval and slightly curved.
- Color: adults range from gray‑brown to light brown; nits are translucent to white, darkening as embryos mature.
- Attachment: lice move freely; nits remain fixed to hair by a cemented base.
These characteristics enable reliable identification of both the insects and their eggs during inspection.