Besides these extreme variations, which appear to be largely dependent on local conditions, great variability exists with respect to the number and size of the ocelli or white-centred spots. In some specimens there are no ocelli on the hind-wings; in others, two, three, or four very minute ones, whilst others have all four very large. Occasionally specimens have a minute ocellus below the large one on the fore-wings. Were it not for the intermediate varieties, there would probably be little hesitation in separating the extreme forms of this insect into several distinct species; but as they are connected by a host of intermediate forms, it is quite impossible even to divide them into varieties.
In a paper communicated to the 'Entomologist' in February, 1889,[52] by Mr. W. W. Smith, the author makes some interesting remarks on the variation of this butterfly, as observed by him in Canterbury and Otago. After pointing out the great diversity exhibited by different specimens in the depth of colouring, and in the number and size of the ocelli, he states that in his opinion the greatest variation occurs during the summers that succeed wet winters. In the year 1888 I had the opportunity of inspecting a most interesting series of this insect, presented by Mr. Smith to the Wellington Museum. They embraced specimens of very varied colouring, and included, amongst other remarkable forms, a male, which was entirely destitute of all ocelli, both on the fore- and on the hind-wings. Amongst these specimens, however, I did not see any resembling those I have described from Nelson and Marlborough. This collection has, I regret to say, since been disposed of by the Museum authorities, and cannot therefore be utilised by New Zealand students.
The larva of this insect feeds on the tussock grass (_Poa australis_). Its length, when full grown, is about 1 inch. The top of the head is furnished with a very large process, which projects forwards. The body is much attenuated towards the tail, which is bifid. The general colour is dull green, with a crimson line on each side and numerous alternate lines of yellow and white. The legs and prolegs are very small. There are four wrinkles on the posterior edges of each segment.