Sub-family TRIOZINAE. The cubitus of the wing has no stalk, the veins forking directly from its junction with the sub-costa. All our species, with one exception, come into the typical Genus _Trioza_: many of them are gall makers in the larval state, others are naked and cling to the under surface of twigs and leaves. The larvae of the gall-makers are broad, oval, flattened creatures, covered with a mealy secretion, the outer margin of the dorsal shield in each case being fringed with fine regular ciliae. Most of the perfect insects are thickset; they range from chestnut brown to reddish yellow; and have clear transparent wings. _Trioza carnosa_ makes a large, oval, fleshy, brightly tinted gall with an irregular opening at the summit, often covering and aborting the foliage of eucalypts about Sydney. The larva of _T. eucalypti_ forms a rounded, hard, woody gall upon the leaves, without any opening on either side until the gall contracts and splits open, when the full grown pupa emerges. _T. casuarinae_ is a very pretty little psylla with dark-barred wings, and its curious naked fish-like larva clings to the slender foliage of the she-oak (_Casuarina_). _T. banksiae_ has a tiny, naked, yellow larva covered with silvery down; it is a rare insect found on the under surface of the honeysuckle leaves. Nearly all these species have been collected within a day’s journey from Sydney, but have a wide range on the eastern coast. The Sub-family PRIONOCNEMINAE was formed by Scott for Walker’s Genus _Tyora_, in which I have placed two species. _Tyora sterculiae_ is a pale green, aphid-like psylla, with long antennae and large transparent wings. The larvae cluster together on the leaves of the Kurrajong, forming white patches over the foliage, and each larva throws out slender white threads, fringing the tip of the abdomen and radiating about the body. _T. hibisci_ is a delicate pale green insect which has been taken on the foliage of _Hisbiscus tiliaceus_, about Brisbane, Queensland, and also on a creeper on the Tweed River, New South Wales. Family 7. Aphids or Plant Lice. APHIDAE. These destructive little creatures are well known to gardeners under different names, such as “smother or green-fly,” “plant lice,” or “blight.” This family contains one of the most destructive and widespread pests that ever attacked cultivated plants, namely the vine louse (_Phylloxera vastatrix_), which has destroyed millions of pounds’ worth of vines, and has followed its host all over the world. Aphids are all small soft-bodied creatures, green, black, or yellow in colour; and at least ten introduced species are to be commonly found in our gardens and fields; but as far as I know, no indigenous aphid is recorded in Australia.