The 1966 Butterfly Definitive Issue

The Territory of Papua and New Guinea (as it was then), together with the Commonwealth of Australia and its other Territories, changed from £sd currency to a new decimal currency on the 14th of February 1966. All stamps expressed in the old £sd currency were withdrawn from issue at the close of business on the 12th and replaced by the new decimal stamps to be issued a the opening of the post offices on the 14th.
The first of the new decimal currency stamps was a set of eleven definitives featuring butterflies of the Territory of Papua and New Guinea and they depicted the following:

lc  Blue Emperor - Papilio ulysses autolycus
3c  White Banded Map Butterfly - Marpesia acilia tervisia
4c  Mountain Swallowtail - Graphium weiskei
5c  Port Moresby Terinos - Terinos alurgis
1Oc  New Guinea Birdwing - Ornithoptera priamus poseidon
15c  Euchenor Butterfly - Papilio euchenor
20c  White Spotted Parthenos - Parthenos sylvia pherekides
25c  Orange Jezebel - Delias aruna aruna
50c  New Guinea Emperor - Apaturina erminea papuana
$1  Blue Spotted Leaf-wing - Doleschallia dascylus
$2  Paradise Birdwing - Ornithoptera paradisea