Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Superfamily: Papilionoidea
Family: Nymphalidae
Subfamily: Danainae
Tribe: Danaini
Genus: Danaus
Species: D. plexippu
Scientific Name: Danaus plexippus
Common Name: Monarch Butterfly

The monarch arrived in New Zealand about 120 years` ago crossing the Pacific from North America. It is New Zealand's largest resident butterfly. Its caterpillar's food is the Swan plant ( Gomphocarpus). Their live cycle is two weeks as a caterpillar, two weeks as a chrysalis and about two months as a butterfly. 
Female Monarchs have darker veins on their wings, and the males have a black spot in the centre of each hindwing from which pheromones are released. Males are also slightly larger. See photo at bottom of this page.

A monarch butterfly caterpillars
Monarch Butterfly Danaus plexippus-003.JPG

1- Danaus plexippus Monarch caterpilla.JPG

1-Danaus plexippus Monarch caterpillar-003.JPG

Monarch Danaus plexippus-13.JPG 

Caterpillar of the monarch butterfly Danaus plexippus-27.JPG 

The caterpillar has just attached itself to a branch in preparation for forming a chrysalis
Monarch Butterfly Danaus plexippus-005.JPG

The next stage of forming a chrysalis
Danaus plexippus Monarch Butterfly-003.JPG

Danaus plexippus Monarch Butterfly-004.JPG

The monarch butterfly chrysalis
Monarch Butterfly Danaus plexippus-006.JPG

The monarch butterfly chrysalis with the developing butterfly's wing patterns just visible.
Monarch Butterfly Danaus plexippus-007.JPG

A chrysalis on a swan plant
Asclepias physocarpa Swan plant -013.JPG

Mating butterflies.
Monarchs mating.JPG


The butterfly of Danaus plexippus male. Notice the black pheromone releasing spot on each hind wing.Monarch butterfly male Danaus plexippus.jpg


Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/