Adult females unusually large in many species (up to 4 cm), usually brightly colored, often red or purple. Cyst stages occur in the soil, on stems or on the trunk in a papery or waxy cyst. Adult females have the apex of the abdomen invaginated to form a marsupium where the eggs hatch.
Until recently, Callipappus was the sole member of the family. Gullan and Sjaarda (2001) placed Platycoelostoma in the group as well. Callipappidae MacGillvray was first used as a family by Koteja (1996a).
Callipappids occur in New Zealand and Australia only. Find a list species from the Australasian region. They are most speciose in Australia where there apparently are several undescribed species (Gullan and Brookes 1998).
The hosts of Callipappus species are not well known because they feed on roots and are difficult to find; ovipositing females occur on nearly any vertical surface in the area of emergence and therefore their location on a host is a poor indicator of their actual feeding host. It is likely that some species feed on Banksia. The hosts of Platycoelostoma include the conifer genera Diselma and Libocedrus.
Callipappids apparently have 4 instars in the female and 5 in the male. No definitive work has been completed on the bionomics of this group, but it is assumed that a generation takes at least 1 year. Callipappus species develop underground as legless cysts in a waxy test where they feed on the roots of the host. In autumn they emerge from the soil as adult females and mate immediately with the large and quite beautiful males. The females move to an oviposition site, invaginate the 3 apical segments of their abdomen into a marsupium, and lay eggs in the marsupial pouch. Soon after oviposition begins, the females become leathery and appear dead. Crawlers emerge from the marsupium, fall to the ground, and begin the cycle again. Platycoelostoma species are similar except feeding occurs on the branches and trunk of the host in a waxy cysttest or under the bark.