noun
- a retractable, forked, scent-producing organ found behind the head of swallowtail butterfly caterpillars, used for defense against predators
Usage: entomology
Examples
- When threatened, the swallowtail caterpillar extends its bright orange osmeterium.
- The osmeterium releases a foul-smelling chemical to deter predators.
- Scientists studied the osmeterium’s role in caterpillar defense mechanisms.
- The forked osmeterium can be quickly withdrawn when the danger passes.
- Each species of swallowtail has a distinctively colored osmeterium.
- The osmeterium appears as two horn-like projections when fully extended.