This species is very abundant in the neighbourhood of Wellington. It has also been taken at Taranaki, Christchurch, Dunedin, Invercargill and Stewart Island, and is probably common and generally distributed throughout the country.
The expansion of the wings is about 1½ inches. All the wings of the male are yellowish-brown; there is a faint transverse line near the base, and a conspicuous darker transverse line running from a little before the apex of the fore-wing to the middle of the dorsum of the hind-wing; there is also a dark spot in the centre of the fore-wing, often containing two white dots. In the female, all the wings are slate-coloured; the transverse lines are very faintly indicated, and the central dot of the fore-wing is reddish-brown. The apex of the fore-wing in each sex is conspicuously hooked, and the termen is bowed and sometimes has a very slight angle in the middle.
Both sexes of this insect are very variable. In the male, the ground colour ranges from dingy-brown to bright orange-brown; the transverse lines differ much in intensity, and in some specimens the central area of the wings enclosed by them is much darker than either the basal or the marginal portions; occasionally there is a series of black markings between the outer transverse line and the termen of the fore-wings, whilst the transverse line itself is frequently edged with a band of paler colouring. The female also varies in the ground colour and in the intensity of the transverse lines, which are sometimes marked by a few black dots.
The larva, according to Mr. Purdie, is light grey, cylindrical, about ⅝ inch in length. It may be beaten in February from an undergrowth of Carpodetus and Aristotelia.
The perfect insect appears from November till March. It frequents dense forest and is often very abundant. The colouring of the upper and under surfaces of its wings, and the shape of the wings are both very protective, giving the moth an exact resemblance to a dead leaf. When disturbed, the insect adds to this deception by keeping its wings quite motionless and rigidly extended, and allowing itself to fall through the air like a leaf. The resemblance in this case to the inanimate object is very perfect, and has no doubt enabled the moth to escape from many enemies. It is, in fact, an extremely interesting example of the simultaneous development of structure and instinct in a useful direction, through the agency of natural selection.
This species is much attracted both by light and by blossoms.
Genus 7.—AZELINA, Gn.
"Face with some projecting hairs. Palpi rather long, obliquely ascending, roughly scaled, attenuated. Antennæ in male thick, simple. Fore-wings with vein 6 from below 9, 7 from below angle of areole, 10 very shortly touching 9, 11 separate, 12 free. Hind-wings normal.
A genus of some extent, specially characteristic of South America. Guenée made a separate genus (Polygonia) of the New Zealand species, but without any point of distinction."—(Meyrick.) (Plate [II]., figs. 54 and 55, neuration of Azelina gallaria.)
We have three species in New Zealand.[[42]]