Allied to _I. sacchari_, Guérin, which damages sugar-canes in Mauritius; but differing in the formation of the ovisac, the presence of the marginal tufts and spinneret tubes in the female, and in other particulars. The male of _I. sacchari_ has not been described. The male of _I. Purchasi_ is probably quite distinct. This species is supposed to have come originally from Australia. It has been very injurious to orange and lemon trees at the Cape of Good Hope and in California. In Auckland it has destroyed whole orchards of the same trees, and in Nelson and Hawke's Bay it is a dreadful pest on all kinds of plants. Tree-growers should especially beware of this insect, and the best plan to adopt would be to burn at once any tree found infested with it. Genus: CŒLOSTOMA, Maskell. N.Z. Trans., Vol. XII., 1889, p. 294. Adult females with antennæ of eleven joints; segmented; naked, active; at gestation becoming stationary and enclosed in a thick mass of white cottony secretion. Anal tubercles absent or inconspicuous. Rostrum and mentum absent in the adult female. Males with prominent, facetted eyes; ocelli absent. Abdomen without tassels. In one New Zealand species the female in the second stage is stationary, enclosed in a thick, hard mass of waxy secretion, of which some account is given in Chap. III. The other species included in this work inhabits a remote and scarcely visited district, and the female has not hitherto been found; it is not possible therefore to include the excretion of wax and the stationary position amongst the generic characters at present. This genus is allied to _Porphyrophora_, Brandt, and to _Monophlebus_, Leach; differing from the former by the presence of an œsophagal orifice, and from the latter by the absence of tassels on the abdomen of the male. In the genus _Ortonia_, Signoret, the female possesses a rostrum and mentum. 66. Cœlostoma zealandicum, Maskell. N.Z. Trans., Vol. XII., 1879, p. 294; Vol. XIV., 1881, p. 226; Vol. XVI., 1883, p. 141. (Plate XX.; Plate XXI., Fig. 1.)