National Geographic : 1957 Aug
@ National Geographic Society + Dangling Larva Awaits the Close of Its Earthbound Existence One of nature's most spectacular events, the trans formation of lowly caterpillar into fragile butterfly, comes alive in these photographs of Heliconius mel pomene and those of Dryas julia on pages 214-215. As the time for change approaches, the caterpillar spins a button of silk from which to hang. Conversion to the chrysalis begins as the caterpillar sheds its old skin, spines and all (above right). Now the creature is entering the enclosed state from which it will emerge a butterfly. (Magnified 5 times.) Chrysalis Discards Larval Skin, + a Last Link with the Past This rare photograph catches the melpomene cater pillar in its final stages, just as the old skin flies free in a crumpled ball (left). Before the old outer layer is shucked off, the insect secretes a new covering of quick-drying material that will serve as shelter during the chrysalis, or pupal, state. Here the new pupal skin covers the developing, upside-down butterfly (magnified 6Y2 times). Biologists believe the pupa's leaflike appendages and pointed fringe may be protective camouflage.