Adult female is red or reddish brown and is covered with a white mealy secretion, a cottony wax, and some long curling coarse yellow threads. There are short lateral filaments on the posteriorabdominal segments. First instars are yellowish red covered with the same white mealy wax. Adult males are red or reddish yellow, large, covered with white mealy wax, and have 2 lateral filaments.
The placement of Phenacoleachia has been an enigma since its description in 1891. In general appearance it resembles a mealybug but it is becoming increasingly evident that it is more closely related to the primitive groups of scale insects such as the ortheziids and margarodoid than to the higher groups such as pseudococcids. Phenacoleachiidae Cockerell was first treated as a family by Obenberger (1957).
Phenacoleachia is known only from the south island of New Zealand and from the New Zealand off shore islands.
Phenacoleachia zealandica (Maskell) is reported primarily from Nothofagus species in the Fagaceae and P. australis Beardsley is from a Pleurophyllum species, a composite.
Little is known about the life history of phenacoleachiids.