CONTRAST COLOURS.--In this class of colouring the fore-wings only are protectively coloured, the hind-wings being very conspicuous. Contrast colouring is well exemplified by several of the insects included in the genus _Notoreas_. The sudden exhibition of the hind-wings during flight dazzles the eye of the pursuer. When the insect immediately afterwards closes its wings and the fore-wings alone are visible, it is extremely difficult to see. This form of protective colouring was also first drawn attention to by Lord Walsingham. (See page 75.) WARNING COLOURS.--Insects, which are unfit for food or nauseous, are not protectively coloured, but on the contrary are rendered as conspicuous as possible. This class of colouring is well illustrated by one of our commonest moths, _Nyctemera annulata_ (Pl. IV., figs. 1 and 2). The principle of warning colours was first discovered by Mr. A. R. Wallace, and is graphically described in Professor Poulton's entertaining work, 'The Colours of Animals.' The possession of nauseous qualities would be of little value to an insect, unless it could be at once recognised by insectivorous animals and avoided as food. If a nauseous insect were not easily identified it would speedily be destroyed by what Professor Poulton ingeniously terms "experimental tasting"; hence, through the process of natural selection, all nauseous species have become very conspicuously coloured. It may be remarked that warning colours are extremely rare amongst the New Zealand species, and I am not aware of any other example than that already given. MIMICRY.--This term is applied to those remarkable cases where a harmless or edible species imitates in form and colouring a highly armed or nauseous species. No instances of this extremely interesting class of protection are yet known amongst the New Zealand _Lepidoptera_, but a very perfect example of mimicry exists between two common introduced species of _Hymenoptera_ and _Diptera_, the well-known honey-bee and the drone-fly. The superficial resemblance between these two insects is very close. The bee, as every one knows, is armed with a powerful sting, whilst the drone-fly is unarmed. In this case it can be seen that if a harmless insect varied in the direction of resembling a formidable or objectionable species it would be a decided advantage to it, and such varieties would tend to be continually preserved and improved, through the operation of natural selection. The subject of mimicry has been alluded to here as it is not impossible that some instances of it may yet be discovered in connection with our native _Lepidoptera_.