The members of the Sub-family PSYLLINAE have the same well-defined conical face lobes, but the stalk of the cubitus is shorter than the stalk of the sub-costa. The larvae may be quite naked, but most of them produce woolly filaments more or less covering them, and form no true lerp scales or galls. The typical Genus _Psylla_ comprises a number of usually small and somewhat stouter insects, many of which cluster in swarms like aphids upon the foliage of wattles and other trees. The eggs, larvae, pupae, and perfect insects may be found on the same twigs. _Psylla acaciae-decurrentis_ is a slender, dark-winged insect remarkable for the length of its slender antennae; it is common upon the black wattle in early summer. _P. acaciae-baileyanae_ is a much smaller yellow species with mottled wings that often swarms over the cultivated “Cootamundra wattle,” and is reported to have destroyed all the flower-buds of this wattle in the neighbourhood of Melbourne in 1905. _P. capparis_ is a mottled winged species that frequents the foliage of _Capparis mitchelli_ in the western scrubs: _P. schizoneurodes_ infests the twigs of the allied “Warrior Bush”; the larvae are covered with flocculent matter and have a globule of liquid substance at the tip of the abdomen; when massed together they look much like “woolly blight” on the apple trees. _P. sterculiae_ is a small brownish species, found upon the twigs of the Kurrajong, and has a wide range over New South Wales. [Illustration: =Fig. 161.=--_Psylla sterculiae_ (Froggatt). The Kurrajong Twig Psylla. (“Agricultural Gazette,” N.S.W.)] Two very curious species are found upon the thick fleshy leaves of our native figs, and one, _Mycopsylla fici_, lays her eggs upon the foliage, the squat grey larvae burying their beaks in the leaf cause a flow of milky sap, under which they hide in small colonies, and when ready to emerge crawl from beneath the viscid mass. Where numerous, they cover the foliage with these sticky patches, and cause the leaves to fall. The perfect psylla is a handsome, dark-coloured insect with long antennae and ample transparent wings. [Illustration: =Fig. 162.=--_Tyora sterculiae_ (Froggatt). The Star-psylla found on the surface of the leaves of the Kurrajong. (“Agricultural Gazette,” N.S.W.)]