Many people are under the impression that scale-insects out-of-doors are not of much consequence. They are aware that in greenhouses and hothouses these insects are a trouble to gardeners, and that they probably injure flowering or fruit-bearing plants in such situations. But they imagine that in the open air, and on large well-grown trees, Coccids do no very great harm; or, if the trees are for a time injured, that recovery and health will come before long, and the pest will disappear. This is not the place in which to controvert this or any other opinion. A work professedly dealing with facts should be as free as possible from controversial discussion. Whatever, therefore, may be the grounds of the opinion just stated, or the reasons for rejecting it, it will be sufficient here to say that there seems to be nothing to lead to the belief that New Zealand is likely to be different from other countries in this respect. To institute a comparison, it would be manifestly absurd to include such countries as England, or Germany, or, on the other hand, India, or Central America, or North Australia--Firstly, because in the greater part, or at least in the northern parts, of Europe the winters are much more severe than in New Zealand, and almost certainly the great cold is injurious to such insects as Coccids. Secondly, because in tropical countries it seems that the too great heat is equally obnoxious to them; and, with the exception of a few species, tropical Coccids are comparatively harmless. But it is to the warmer temperate or the subtropical regions that we must look for comparison--regions where there is neither too scorching a summer nor too ice-bound a winter. And, for this purpose, we have only to take such lands as California, Florida, the South of France or Northern Italy, the Cape of Good Hope, the southern regions of Australia, &c. The experience of these is, that some species of Coccids do injure, in every way, whether as regards ornamental or commercial value, a number of trees and plants on which the people of the country depend largely for subsistence or profit. In the South of France the olive industry has been in some years greatly cut down. In Florida, California, Australia, the Cape of Good Hope, oranges and apples have been so damaged that the value of an orchard or a grove has been reduced sometimes by 80 per cent. It may be said, moreover, that even in tropical countries the attacks of scale-insects are often most damaging: in Mauritius the sugar-cane and in Ceylon the coffee plantations have suffered from their ravages. The experience of American fruit-growers is certainly not to be despised, and the fact that both in California and Florida the people strain every nerve to get rid of the insect pests on open-air trees would seem to be distinctly against the notion that these little enemies can be neglected with impunity.