Caterpillar emergence The fourth instar caterpillar emerges from the gentian flower shortly after it has moulted

The newly-moulted caterpillar chews a hole in the flower-head from the inside out and crawls outside. As the picture on the right shows, several caterpillars can develop in and emerge from the same gentian flower. The caterpillar then crawls onto the bracts of the flower, or onto the leaves of the gentian, and lowers itself to the ground on a silken thread.
		The picture to the left is a scanning electron micrograph of a fourth-instar caterpillar that has just emerged from a gentian. The caterpillar is quite difference in appearance from the third-instar caterpillar. It has almost no hairs on the upper surface and has a few special glands here that the third instar caterpillar lacks. The caterpillar will wait on the ground until it is discovered by a worker ant. The caterpillars usually leave the plant during the morning or evening, when the chances of drying out are quite low, but the chance of being discovered by an ant are high.