In order to render this work complete a second volume is necessary, which should include the large number of other destructive insects preying upon various plants. For example, the "pine-blight" (_Kermaphis_), the "American blight" (_Eriosoma_), the "black leech" (_Tenthredo_), the cabbage caterpillar, the turnip "fly," the various aphides on roses, geraniums, &c., the grass-grub (_Odontria_), the codlin-moth, the borers, weevils, wireworms, and a number of others are in different places damaging trees and plants, and it would be useful to collect in one volume information regarding them. The author has had in contemplation the preparation of such a volume, and it is hoped that it may be at some future time published. Meanwhile the present is offered as, at least as far as it goes, a full description of one of the most general as well as the most noxious families of plant-parasites. The plates have been especially prepared with a double object: first, that gardeners and tree-growers might be able easily to recognize the kind of insect which might happen to be damaging their plants; and, secondly, that the student who should desire to know more of this curious family might have enough details indicated to guide him in his investigation. For the first purpose the figures have been coloured as near to nature as possible; for the second a few anatomical details have been introduced. The printing of these plates has been executed by Mr. Potts, lithographer to Mr. A. Willis, of Wanganui, and it is hoped that the reader may be well satisfied with the care and trouble which have been bestowed upon them. The author is sensible that this volume may contain numerous imperfections; but these will not, he trusts, be attributed to culpable ignorance or carelessness. EXPLANATION OF TERMS USED IN THE FOLLOWING PAGES. _Abdomen._ The posterior half of the body of male or female, whether joined to the anterior half or slightly separated, segmented or not. _Abdominal cleft._ A narrow slit in the extremity of the abdomen of Lecanidinæ and the full-grown _Hemicoccidinæ_ only. (Plate ix., Fig. 1, _b_, _c_.) On the upper side of the body are seen the _Abdominal lobes_, two minute, divergent, triangular or conical, excrescences, one on each side of the cleft, in _Lecanidinæ_, usually bearing one or more hairs. (Plate xi., Fig. 3, _b_, _c_.) _Abdominal spike._ A more or less long, tubular or semi-tubular, pointed process terminating the abdomen of the male in all species, and serving as a sheath for the penis, which is a long, white, soft tube with recurved hairs. (Plate ii., Fig. 3; Plate xxi., Fig. 1, _k_.) _Anal ring, anogenital ring._ An orifice situated near the abdominal extremity of the female, either simple or compound, hairless or bearing several hairs. (Plate ii., Fig. 1.)