What do adult lice larvae look like? - briefly
Adult lice are wingless, elongated insects about 2–4 mm long, with a flattened, dorsoventrally compressed body covered in tiny, translucent scales that give a pale grayish appearance. Their three pairs of legs end in clawed tarsi adapted for clinging to hair shafts.
What do adult lice larvae look like? - in detail
Adult head lice measure 2–4 mm in length, have a flattened, elongated body, and display a gray‑white to tan coloration. The exoskeleton is smooth, lacking scales or setae, which aids movement through hair shafts. Six short legs emerge from the thorax, each ending in claw‑like tarsi that grasp individual hair strands. Antennae consist of five segments, are slender, and bear sensory receptors. Compound eyes are present on the head, providing limited vision. The abdomen contains three visible segments, each bearing a pair of spiracles for respiration.
Immature stages, commonly called nymphs, resemble miniature adults but differ in size and pigmentation. Nymphs progress through three molts before reaching maturity, with each instar increasing in length by roughly 0.5 mm. Early instars appear translucent to pale yellow, becoming progressively darker with each molt. Leg length remains proportionally shorter than in adults, and the claw tips are less developed, limiting mobility on thicker hair. Antennae retain the five‑segment structure but are more delicate. Spiracles are visible only after the second instar.
Key visual distinctions between mature lice and their younger forms:
- Size: adults 2–4 mm; first‑instar nymphs ~1 mm.
- Color: adults gray‑white to tan; nymphs range from translucent to light brown.
- Leg development: fully formed claws in adults; reduced claw curvature in early nymphs.
- Body segmentation: abdominal segments become more pronounced with each molt.
- Visibility of spiracles: absent in first instar, evident from second instar onward.
These characteristics enable precise identification of the insect at any developmental stage.