Osma means smell in latin and Osmeterium is defensive orgain with pungent smell in Papilionidae that is Swallowtail butterflies. When I was trying my best to get a shot of this beauty, a wasp appeared from nowhere and hovered close to the caterpillar. That it when this cute looking larva revealed its vibrant crimson red weapon. I was amazed looking at that through viewfinder and now I obviously wanted to make an attempt to capture that. Caterpillars or any animals when threatened try to hide themselves in a spot ASAP and that is what even this caterpillar did after showing the tentacular structure twice. It was approaching internal; main branch side of the plant and before disappearing into it completely wasp made another attempt giving me this not so bad record. So here is a collage, where you can see a retracted Osmeterium bove and then how it looks when exerted out for defense display. The bifurcated look of the Osmeterium coupled with eye spots on caterpillar are also to make them appear like a snake to fool their predators.
The Common Mormon is a common species of swallowtail butterfly widely distributed across Asia. This butterfly is known for the mimicry displayed by the numerous forms of its females which mimic inedible Red-bodied Swallowtails, such as the Common Rose and the Crimson Rose.