CHRYSOPHANUS SALUSTIUS, Fabr.
(Chrysophanus salustius, Fabr., Butler, Butterflies of N. Z., Trans. N. Z. Inst. x. 263. Chrysophanus rauparaha, Fereday, Trans. N. Z. Inst. ix. 460. Chrysophanus maui, ib. x. 252.)
(Plate [XII]., fig. 18 ♂, 19 ♀, 20 and 21 under side; Plate [XIII]., figs. 2, 3, 4, and 5 varieties.)
This pretty little butterfly appears to be very common in most parts of New Zealand. I have records of its occurrence in abundance at various localities, from Napier southwards to Invercargill.
The expansion of the wings varies from 1 to 1½ inches. On the upper side all the wings are brilliant shining copper, with black markings. Fore-wings with three spots near the middle, then a row of black spots, often forming a band nearly parallel with the termen, another row on the termen, generally touching the narrow black border of the wing. Hind-wings resembling fore-wings, except that there is only one elongate spot in the centre, and the terminal series of spots is nearly always separated from the black border. In the female the black spots are united and form bands, those on the termen often having violet or blue centres. The veins in both sexes are indicated by black lines, which are often double in the male, when the vein itself is coppery. On the under side the fore-wings are orange-brown, bordered with yellow; the spots resemble those of the upper side, except that the terminal series are generally faint or obsolete towards the costa. The hind-wings vary from light yellow to dull brown; the spots are dull greyish, the posterior series often having white centres.
From the foregoing it may be seen that the variation in this insect is considerable. After a careful examination of a large number of specimens taken at various localities in both North and South Islands, I am, however, unable to find characters of sufficient constancy to entitle any of the forms to specific rank. The most striking of these varieties appears to be that described by Mr. Bates as Chrysophanus feredayi.[[55]] (See Plate [XIII]., fig. 2, upper side; Plate [XII]., fig. 21, under side.) On the upper surface it has the central series of spots almost forming a band in the male, and the coppery ground colour is paler than in the typical form. On the under side the borders of the fore-wings, and the whole of the hind-wings are dull brown. This form closely resembles C. rauparaha, Fereday.[[56]] C. maui, Fereday, is evidently that variety of the male having the veins bordered with two fine black lines. Mr. Fereday states that he has never been able to find the female of his C. maui. This is readily accounted for by the fact, that the female of C. maui is nothing more than the female of C. salustius.
Recently two very remarkable aberrations of C. salustius have come under my notice; one captured by Mr. Hawthorne at Karori, in which the hind-wings are almost entirely suffused with blackish-brown, excepting a small patch of copper colour near the centre, and two patches on the termen. Another specimen, taken by Mr. Grapes near Paraparaumu, has the fore-wings also suffused with blackish-brown, except near the middle, where there are five coppery patches between the veins. On the under side there are six large oblong spots near the termen of the fore-wings, and a series of dusky oblong spots on the hind-wings. (See Plate [XIII]., fig. 3, fig. 4 under side.) Plate [XIII]., fig. 5, represents another variety discovered by Mr. Grapes on the coast near Paikakariki, in the Wellington district. It is remarkable for the bright blue terminal spots which are present in both sexes.
The eggs of C. salustius, when first deposited, are pale green with yellow reticulations, the whole egg having a honeycombed appearance when magnified. They become uniform pale yellow before hatching. The young larva is shaped somewhat like a wood-louse. The head is quite hidden by the three anterior segments, which are much larger than the rest. After the first moult the larva becomes bright green, with a crimson line down the back; the head is then larger, and the three anterior segments considerably reduced. Unfortunately the life-history could not be investigated beyond this point, as the larvæ all died. The time of year when this occurred was late autumn, and it therefore seems probable that the larvæ hibernate and undergo their transformation early the following spring.
The perfect insect first appears in November and continues abundant until the middle or end of February. Specimens of what I believe to be a second brood may be taken in March and April if the weather be fine, but in stormy seasons these are frequently not observed. I have also noticed that the autumnal specimens are usually smaller and paler in colour than those captured in the spring.
This butterfly frequents open situations, and in fine, sunny weather it is often very common.