What do louse larvae look like? - briefly
Louse nymphs are tiny, oval, cream‑colored insects without wings, possessing six legs and a segmented body that darkens with development. They measure roughly 0.5–1 mm and are covered in fine hairs.
What do louse larvae look like? - in detail
Lice nymphs, often called larvae, emerge from eggs and pass through three successive instars before reaching adulthood. Their morphology is consistent across the three major species that infest humans—head lice, body lice, and pubic lice—though minor variations in size and coloration exist.
The first instar measures approximately 0.5 mm in length, appearing translucent or pale yellow. The body is elongated, cylindrical, and segmented into three primary regions: head, thorax, and abdomen. The head bears a pair of short, reduced antennae that are barely visible under magnification. Mouthparts are adapted for piercing skin and consist of a slender, piercing-sucking stylet.
Three pairs of legs originate from the thorax. Each leg ends in a claw equipped with a tiny hook, allowing the nymph to cling tightly to hair shafts or clothing fibers. Legs are short relative to the body, giving the insect a compact appearance.
As the nymph progresses to the second instar, size increases to about 0.7 mm. Pigmentation deepens to a light brown, and the exoskeleton becomes more sclerotized, providing greater rigidity. The second instar retains the same basic body plan, but the eyes become more distinct, and the mouthparts lengthen slightly.
The third instar reaches a length of 1.0–1.2 mm and displays a darker brown or reddish hue. Body segmentation is more pronounced, and the legs are fully developed with stronger claws. At this stage, the nymph resembles an adult in overall shape but lacks fully mature genitalia.
Key visual characteristics of lice larvae:
- Length: 0.5 mm (first instar) → 1.2 mm (third instar)
- Color: translucent → light brown → dark brown/red
- Body shape: elongated, three‑region segmentation
- Antennae: short, reduced, often invisible without magnification
- Mouthparts: piercing‑sucking stylet for blood feeding
- Legs: three pairs, each ending in a hooked claw for attachment
- Eyes: become more visible from the second instar onward
These details enable accurate identification of lice nymphs during inspection and inform effective control measures.