Fleshy organ that can be extended from behind the head by swallowtail caterpillars that emits an unfavorable odor to fend off predators
fleshy structure on some larvae, often discharging odorous chemicals.
The osmeterium is a fleshy organ found in the prothoracic segment of larvae (caterpillars) of Swallowtail butterflies including Birdwings and the `-prominent (Notodontidae) moths. This organ emits odorous compounds believed to be pheromones. Normally hidden, this forked structure can be everted when the caterpillar is threatened, and used to emit....
an eversible forked pouch in Papilionidae located middorsally on the prothorax.
osmeterium A gland found on many caterpillars that secretes an unpleasant smelling substance as a defense against predators.