Caterpillar chrysalis formation. Larval stage of a small tortoiseshell (Aglais urticae) butterfly forming a chrysalis. This butterfly's caterpillar forms a chrysalis hanging from stems or branches. It secures itself with a silken pad then splits its skin (moults) hooks itself into the silken pad. Later, after around 12 days, the butterfly emerges from a near-transparent chrysalis that reveals the wing colours.