The members of the Genus _Asterolecanium_ are represented in Australia by the introduced “oak scale” _Asterolecanium quercicola_, a typical form which, half buried in the infested bark at the tips of the branches, is covered with a waxy, greenish yellow, rounded scale; when numerous it causes the tips of the branches to die back. _A. acaciae_, when numerous, aborts the bark and twigs of _Acacia longifolia_ and is covered with dull brown and white shields; and with _A. stypheliae_, with its raised, shining, oval, bright yellow tests, found on a number of different shrubs, are both native species with a very wide range over Australia. The Genus _Rhizococcus_ is represented by 8 species, found chiefly upon the twigs of wattles (_Acacia_) and she-oaks (_Casuarina_); and the cosmopolitan Genus _Eriococcus_ by 17 species. Several species of _Eriococcus_ enclosed in their egg-shaped, white-felted sacks are very common in the forest, clustering over and often killing the young trees. _Eriococcus coriaceous_ varies from white to yellow in colour; the sacs are oval, with a distinct anal opening on the summit; they infest the foliage and twigs of many young Eucalypts. _E. paradoxus_ is a somewhat larger, sticky insect; they mass together in regular lumps on the twigs of the same trees: while _E. eucalypti_, as far as my experience goes, is never found on gum trees, as its name implies, but upon the prickly twigs of _Bursaria spinosa_, and its sacs are more depressed and have a browner tint. [Illustration: =Fig. 167.=--_Eriococcus coriaceous_ (Maskell). The Eucalyptus scale. Natural size and enlarged. (Original photo. T. Kirk).] The typical _Dactylopius_ are free-moving insects, often crawling about until their final stage, when they become covered or surrounded with flocculent woolly matter. _Dactylopius albizziae_ is common on the black wattle, and is sometimes a pest in wattle plantations; it is a blackish-blue berry-shaped coccid surrounded with and lightly clothed on portions of the dorsal surface with white mealy and woolly filaments. _D. aurilanatus_ is chiefly confined to the branchlets of _Araucaria bidwilli_, or “Bunya Bunya.” It is very abundant at times on these trees in the Sydney gardens, and is easily recognised by the broad lines of sulphur-yellow meal or down across the dorsal surface. _D. lobulatus_ is an oval coccid, hiding under loose bark on the trunks of the blue gum, _Eucalyptus globulus_; it is so thickly clothed with white mealy secretion forming filaments round the edges that its form and colour are quite hidden.