100 Kina - Elizabeth II Queen Alexandra Butterfly

Papua New Guinea's butterfly coinage series was introduced partly to distinguish the young nation's commemorative program from the generic wildlife issues flooding the Pacific collector market in the late 1980s. The Queen Alexandra's Birdwing — the world's largest butterfly, with wingspans reaching 28 cm in females — is endemic to Oro Province and had been listed under CITES Appendix II since 1975, making its appearance on legal tender a deliberate assertion of conservation policy by the Bank of Papua New Guinea.

Specimens from the 1990 issue carry a slightly different die polish than later strikes in the series, detectable under magnification at the field near the denomination.