How does a louse nymph hatch from its egg?

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human head louse — louse Human head louse (*Pediculus humanus*).

When a louse nymph is ready to hatch from its egg, it initiates the process by sucking in air through its mouth. This air travels through the alimentary canal and accumulates behind the nymph, building enough pressure to force off the egg cap, known as the operculum.1

In many species, the nymph also utilizes a specialized sharp, platelike structure located in its head region, called the hatching organ, to help open the operculum. Once the nymph emerges, it resembles the adult but is smaller, uncolored, and possesses fewer hairs.1