Introduction
The genus Cressida comprises of a single species which is endemic to the Australian region. It has several unusual characteristics. The antennae for example are straight, not recurved as they are in all other Papilioninae. Less obvious is the fact that the female has an abdominal pouch (sphragis) which projects after fertilization and prevents further her from mating with other males. This feature is only found elsewhere only in the primitive neotropical genus Euryades, and in the Parnassiinae.
Cressida cressida is found in eastern Australia, Papua New Guinea and the Torres Strait islands.
Habitats
This species inhabits open lightly wooded areas at elevations between sea level and about 500m.
Lifecycle
The egg is deep yellow, dome shaped and adorned with numerous raised orange tubercles. It is laid singly on Aristolochia (Aristolochiaceae). When fully grown the caterpillar is maroon with creamy markings and short lateral and dorsal tubercles, some of which are cream while some are maroon. When ready to pupate they leave the foodplant and walk with a jerky movement, covering quite long distances in a series of short rapid bursts.
Adult behaviour
Males establish territories and patrol regularly back and forth across them in search of females.