The TRYPETIDAE comprise the true “fruit flies,” many of them very handsome little creatures; some of them form regular galls in the twigs of plants; others with their needle-like ovipositors puncture the ripening fruit, depositing their eggs beneath the skin; the maggots cause the fruit to rot, often before it can be gathered, and thus do a great deal of damage in Australian orchards. The Queensland Fruit-fly, _Dacus (Tephritis) tryoni_, ranges from Queensland (where it probably originally infested native bush fruits) into N.S. Wales, and is now a serious orchard pest in both States. It is a dull brown insect marked with yellow, about the size of a large house fly, with a rather wasp-shaped body, and large transparent wings. I have described several other allied species coming into Australia from the Islands in damaged fruit, “Notes on Fruit-maggot Flies with Descriptions of New Species” (Agr. Gazette N.S. Wales 1899). _Dacus (Tephritis) psidii_ was bred out of guavas imported from New Caledonia; it is about ¼ of an inch in length; is dull yellow, with the thorax distinctly striped, and the abdomen black; the transparent wings are thickly mottled with brown. Tryon says that it is a common fruit-fly pest in Queensland, damaging bananas and other fruits. _Trypeta musae_ was obtained from bananas brought from the New Hebrides: it is a slightly larger fly, with the head and thorax dull yellow; it has no distinct dorsal stripe on the thorax, and the wings are very thickly mottled. _T. bicolor_ is a larger native species with reddish brown head and thorax; with black body; with beautifully mottled black wings having the base and sides unclouded. I have taken it on the trunks of wattle trees near Bathurst, N.S. Wales. The “Mediterranean Fruit Fly,” _Ceratitis (Halterophora) capitata_, first recorded from oranges brought from the Azores to London, was described by Macleay in 1826; it has a wide range, and was introduced into New South Wales some years ago; it is now one of the most serious pests that orchardists have to fight. It is a smaller more thickset fly than the Queensland pest, with the thorax dark metallic brown, and the wings richly variegated. The male is remarkable in having a pair of spatulate hairs, like a second pair of antennae, springing out in front between the eyes. _Trypeta poenia_ is a tiny little fly with a grey pubescence over the thorax and abdomen; the thorax is finely mottled, and the delicate wings are very finely but thickly marked with dark brown; I have taken this species when beating the low scrub in the western country round Condobolin, N.S. Wales. _Lonchaea splendida_ is a very brilliant metallic green fly with pale smoky wings; it is smaller than a house fly, with a much more elongated body; its larvae infest decaying tomatoes, potatoes, egg-fruit and other solanums; it has a wide range from the Pacific Islands and New Zealand, over Australia.