What does a louse look like up close? - briefly
Up close, a louse is a tiny, flattened insect about 2–4 mm long, with a hard, brownish exoskeleton, six legs adapted for grasping hair shafts, and a head bearing short antennae and chewing mouthparts. Its body is segmented into a head, thorax and abdomen, each covered with fine hairs that aid movement across the host.
What does a louse look like up close? - in detail
A louse observed under magnification reveals a compact, dorsoventrally flattened insect approximately 2–4 mm in length for the head‑lice species and slightly larger for the body‑lice species. The exoskeleton is chitinous, giving a smooth, glossy surface that ranges in color from pale gray to brown, depending on species and engorgement with blood.
The body is divided into three distinct regions:
- Head – equipped with a pair of short, slender antennae bearing sensory pits; compound eyes are reduced to simple ocelli; mouthparts form a piercing‑sucking proboscis adapted for feeding on host blood.
- Thorax – bears three pairs of legs, each ending in clawed tarsi that grasp hair shafts or clothing fibers; legs are relatively short, limiting mobility but enhancing grip.
- Abdomen – consists of seven visible segments; each segment is covered by overlapping plates (tergites) that provide flexibility; spiracles are located laterally for respiration.
Additional features include:
- A dorsal carapace that shields the thorax and abdomen.
- Minute setae (hair‑like structures) distributed sparsely across the body, aiding in sensory detection.
- A ventral opening (anal groove) for waste elimination.
When alive, a louse may appear slightly translucent, allowing internal blood to be seen through the cuticle. After feeding, the abdomen expands noticeably, giving the insect a plumper silhouette. The overall morphology reflects an obligate ectoparasite specialized for clinging to hair or fabric and for rapid blood extraction.