The armoured scale insect family Diaspididae is one of ten families of plant-sucking scale insects present in New Zealand, and this family has three unique features. The first feature is that the stomach of armoured scale insects is not directly connected to the hind gut, so they do not produce honeydew; the second is their armour or scale cover, in which they incorporate the cast skins of their juvenile moults; and the third feature is the fused segments of the posterior part of the abdomen called the pygidium. In this Fauna the adult females of all 49 species of Diaspididae known from New Zealand, except the Leucaspidini, are described and illustrated. Four new genera and seven new species are described, and nomenclatural changes are noted. The 1st- and 2nd-instar nymphs of all the endemic species and of four Australian species that are of systematic interest are also described and illustrated. Keys to allow separation of adult females of all genera and species are included. Additional features of this Fauna include: a brief review of earlier work on the Diaspididae in New Zealand; discussion of the biology and life cycle, scale cover formation, natural enemies, distribution, host plant associations including galls, and economic importance; a guide to methods for slide-mounting Diaspididae as used in the NZ Arthropod Collection.