Pascoe described some of ours (Annals of Nat. Hist. 1872), and the Journal of Entomology 1860. Macleay described others in 1871; Reitter in 1876–77; Olliff (Proc. Linn. Soc. N.S.W. 1886); and later Blackburn (Trans. Royal Soc. S.A. 1891). Family 16. COLYDIDAE. These are small, reddish brown or black beetles, elongate in form, with four jointed tarsi, the coxae of the two pairs of fore-legs globular, and those of the hind legs transverse. They are usually found under dead or decaying bark, or among rotten wood. Several members of the Genus _Bothrideres_ are found about Sydney; they have the thorax flattened and the elytra ribbed. About 70 species of this family have been described from this country, chiefly by Macleay 1871; Pascoe in the Journal of Entomology 1860; Reitter in 1877 in several German journals; and later by Blackburn 1891; and Olliff in the Memoirs of the Australian Museum 1889 on species from Lord Howe Island. Family 17. RHYSODIDAE. This family consists of only a few known species; Olliff has described one species, _Rhysodes lignarius_ (Pro. Linn. Soc. N.S.W. 1885), a pitchy black shining beetle about ⅓ of an inch in length; it was found in rotten wood at Yass, N.S.W. Family 18. Bark Beetles. CUCUJIDAE. The members of this group are very curious beetles, most of our species being found under dead bark on the trunks of the smooth gums; both the beetles and their larvae have adapted their form in such a remarkable manner to their surroundings that they are often as flat and thin as a bit of paper, while others living in more roomy quarters are quite normal in shape. _Hectarthrum brevifossum_ is a slender, somewhat cylindrical, shining black beetle, with thickened antennae composed of eleven bead-shaped joints; the head is depressed in front, with the thorax more elongated, and the slender ribbed elytra rounded at the tips. _Platisus integricollis_ is a reddish brown beetle, the basal joints of the antennae elongated and the apical ones bead-shaped; the head is angular, buried in the short broad thorax; the body is flattened, with the elytra slightly ridged round the edges. The larva is as flat as a knife blade, with a large head armed with stout jaws; the thoracic segments are furnished with short thick legs; it has seven simple flattened abdominal segments, with an eighth spade-shaped one, on which is a four-pronged trident-like process standing up at the apex, and a small spine at either side. The insects both in the beetle and the larval stage are often to be found under the same bit of bark.