What does an adult louse look like? - briefly
An adult louse is a tiny, wing‑less insect 2–4 mm in length, featuring a flattened, elongated body, six legs with hooked claws, and a gray‑brown coloration. Its head bears a pair of antennae and chewing mouthparts for blood feeding.
What does an adult louse look like? - in detail
Adult lice are small, dorsoventrally flattened insects measuring approximately 1–3 mm in length. Their bodies consist of three distinct regions—head, thorax, and abdomen—each bearing characteristic structures.
The head bears a pair of short, filiform antennae, each composed of five segments. Compound eyes are present, though reduced, and are positioned laterally. Mouthparts form a piercing‑sucking apparatus (the labium) adapted for feeding on blood.
The thorax supports three pairs of legs, each ending in a claw that enables firm attachment to hair shafts. Legs are relatively long compared to body size, facilitating rapid movement along the host’s hair.
The abdomen contains ten visible segments. In females, the abdomen is more convex and expands to accommodate egg production; in males, it remains flatter and narrower. Both sexes display a translucent to brownish coloration, sometimes with a faint gray hue, depending on the species and the host’s blood.
Key morphological details:
- Length: 1–3 mm (varies by species)
- Color: translucent, gray‑brown, sometimes reddish after a blood meal
- Body shape: flattened, elongated, three‑segmented
- Antennae: five‑segmented, short
- Eyes: reduced compound, lateral
- Mouthparts: siphoning proboscis for blood extraction
- Legs: three pairs, each with a single claw
- Abdomen: sexually dimorphic; females larger, abdomen distended with eggs
These features collectively define the mature stage of the insect, distinguishing it from nymphal forms and from other ectoparasites.