The TESSARATOMINAE are usually large insects found upon plants, and among them are several destructive species. Among a number of hemiptera submitted to D’Horvath for identification were two species, viz., _Rhoecocoris (Oncoscelis) sulciventris_ and _Stilida indecora_, which both in the larval and perfect state swarm over the orange orchards in the north of N.S. Wales and, by sucking up the sap of the stalks, cause the unripe oranges to fall. Their habits and life history being identical, _Rhoecocoris (Oncoscelis) sulciventris_, which was identified by Olliff in the Agricultural Gazette N.S.W. 1892, I at first confused with _Stilida indecora_ (Ag. Gazette, N.S.W., 1901). _S. indecora_ is of a more reddish brown tint than _R. sulciventris_, with the dorsal surface of the thorax not punctured, and the apical areas of elytra more bell shaped, while the venation is much finer; while the thorax of _R. sulciventris_ is distinctly punctured and the anterior edge of the apical area of the elytra is broadly rounded. _Oncomeris flavicornis_ is our largest Australian plant bug, over 1½ inches in length, of a broad shield shape, over ¾ of an inch across the rounded thorax, and of a general dark reddish brown almost black colour on the dorsal surface; each elytron is richly marked on the basal half with bright yellow, and the apical portion is rich metallic purple. It comes from the tropical scrubs of N. Queensland. In the Sub-family DINIDORINAE we have _Megymenum insulare_, a typical form very common on the foliage of the low scrub of the semi-tropical forests of N.S. Wales and Queensland. It is of a general chocolate brown tint, with the inner apical markings of the elytra dull white; it measures just under ½ an inch; the sides of the head and the front of thorax are furnished with short angular spines, which are also present round the outer edge of the abdominal segments; and the whole of the dorsal surface is rugose. The immature larvae are brown, flattened, and fringed right round with bract-like processes. Family 2. Gum-tree Bugs. COREIDAE. This group contains bugs in which the scutellum does not extend as far back as the middle of the body; the head is generally furnished with four-jointed antennae inserted above on the sides of the head; there are two ocelli; and the sheath of the proboscis consists of four segments. Many species have the femora of the hind legs dilated or armed with blunt spines. The majority are dull coloured insects that have no distinctive common name in Australia, so for want of better, I propose to define them as “Gum-tree bugs,” as many typical forms feed upon the young shoots of our gum trees (_Eucalyptus_). In America they are sometimes called “Squash Bugs” from their fondness for pumpkin plants. Over 1,500 species have been described and placed in 29 sub-families; and they are well represented in Australia.