The Coccididæ, in some parts of the world, excrete various substances which are of commercial value, as, for example, shellac, "manna," candle-wax, &c. Cochineal is not in the same category, as it appears to be a colouring-matter pervading every cell of the tissues of the insect from which it is extracted--_Coccus cacti_. But there is no need to dwell here upon the ordinary excretions of the New Zealand insects, as they appear to be not sufficient either in quantity or quality for any practical service. The fibrous puparia of the _Diaspidinæ_ appear to be quite useless. The tests of the _Lecanodiaspidæ_, such as _Ctenochiton perforatus_, _Inglisia ornata_, &c., although more or less waxy (but of very brittle material, often more like glass) are much too insignificant to repay any trouble taken to collect them. Of all the family, _Cælostoma zælandicum_, in its second stage, seems to produce the greatest amount of material, its large, hard, waxy tests being very thick and solid, and often clustered in hundreds on a root or a twig of Muhlenbeckia; but, supposing this substance (of which the true chemical nature[D] is not yet known) to be fit for some purpose, there does not seem to be any means of cultivating the insect to profit. _Dactylopius alpinus_ produces in alcohol a rich red tint, and this not by way of excretion, but from the colouring matters of its tissues, as in the case of _Coccus cacti_; but here, again, the rarity of the insect and its out-of-the-way habitat would be a bar, even if nowadays it were worth while to cultivate a New Zealand cochineal. At present, therefore, there seems no reason to believe that the Coccididæ of this country are likely to furnish any products of a useful or commercial character. [D] A small quantity was submitted to Mr. Skey, Colonial Museum Laboratory, for analysis, no more being available at the time. Mr. Skey considered it as a new substance, probably of the nature of a gum, not resinous; but further examination of larger quantities is necessary.