Part 71

We have two species in New Zealand.

{114}EREBIA PLUTO, Fereday.

(Erebia pluto, Fereday. Erebia merula, Hewitson, Ent. Mo. Mag. xii. 10 (1874). Oreina othello, Fereday, Trans. N. Z. Inst. viii. 302, 304, pl. ix. (1876). Percnodaimon pluto, Butl., Ent. Mo. Mag. xii. 153 (1876); Catalogue of N. Z. Butterflies, 10.)

(Plate XI., fig. 8 , 9 , 10 under side.)

This fine butterfly has occurred plentifully on many mountain-tops in the South Island, from Nelson to Lake Wakatipu. It has never been observed in the North Island.

The expansion of the wings of the male is 1¾ inches, of the female 2 inches. On the upper side all the wings are a very rich bronzy-black. The fore-wings have a paler patch near the apex, containing two small, and three large black ocelli with white centres; these ocelli are usually joined together. On the under side all the wings are considerably paler and greyer. The hind-wings have a series of pale spots near the termen, and a paler shade across the middle.

The insect varies chiefly in the number of ocelli. On the upper side of the fore-wings there are sometimes only four, the minute ocellus on the costa being absent, whilst occasionally a small extra ocellus appears below the normal series. On the under side this last-mentioned ocellus is very frequently, but not invariably, present. In some female specimens an extremely minute ocellus may be detected on the upper surface of the hind-wings near the termen. On the under side of the hind-wings in both sexes the series of pale terminal spots are often absent, and the general depth of the colouring varies considerably.

Mr. Fereday has described and figured a very interesting variation occurring in the structure of the costal veins of this species, vein 11 of the fore-wings sometimes running into 12 (see Plate I., fig. 26), and sometimes being entirely absent (fig. 25). After reading Mr. Fereday's article I examined the specimens in my own collection, and found that all those taken on Mount Arthur and on Mount Peel, in the Nelson district, had veins 11 and 12 joined, whilst the two specimens I took on Mount Enys, Castle Hill, West Coast Road, had vein 11 absent. As, however, Mr. Fereday has specimens exhibiting both forms of neuration, from Castle Hill and from Mount Hutt, I do not think it likely that the peculiarity is confined to butterflies from any particular locality. Like Mr. Fereday, I have observed that the specimens having veins 11 and 12 joined, are smaller than those having vein 11 absent.

The perfect insect appears in January, February and March. It frequents shingle slopes on mountains, at elevations ranging from 4,000 to 6,000 feet above the sea-level. Sometimes the butterflies occur in considerable numbers, flying in a lazy, aimless manner in the scorching sunshine, but instantly retreating into crevices between the stones when the sun is obscured. I have observed that this species is most abundant in the neighbourhood of the carpet grass, on which I fully anticipate its larva feeds. It seldom, however, settles on this grass, preferring to alight on the shingle, which, owing to the rarefied air existing at such high elevations, soon becomes intensely heated by the sun's rays.

When disturbed this insect flies with considerable rapidity and thus often eludes the net, so that the capture of a good series of specimens on a rugged mountain-top is usually very exciting, if not actually dangerous work. As with many other {115}insects, mountain ranges are more prolific in this butterfly than isolated peaks. Mount Peel, situated to the west of Mount Arthur, is the best locality I know of for this and many other Alpine species. Its gentle slopes enable the collector to work with perfect ease and safety, whilst the patches of rich soil occurring nearly to the top of the mountain support an unusually varied Alpine flora of great interest.

EREBIA BUTLERI, Fereday.

(Erebiola butleri, Fereday, Trans. N. Z. Inst. xii. 264; Catalogue of N. Z. Butterflies, 19.)

(Plate XI., fig. 11 , 12 , 13 under side.)

This interesting butterfly was described from three dilapidated specimens captured by Mr. J. D. Enys at Whitcombe's Pass, Canterbury, on March 8, 1879, at about 4,000 feet above the sea-level. From that time I believe no other specimens had been found until January, 1894, when I took quite a large number on the Humboldt Range, at the head of Lake Wakatipu, at elevations ranging from 4,000 to 5,000 feet above the sea-level.

The expansion of the wings of the male is 1-5/8 inches, of the female 1½ inches. On the upper side all the wings of the male are smoky-brown; the fore-wings have a large black ocellus near the apex, enclosing two white dots, followed by a smaller ocellus towards the dorsum; the hind-wings have three black spots near the termen, sometimes enclosing white dots. Occasionally these ocelli are surrounded by a patch of deep reddish-brown. The female is much paler, with large patches of yellowish-brown surrounding the ocelli. On the under side the fore-wings of the male are smoky-brown, with an irregular blotch of reddish-brown near the apex, surrounding a small white-centred black ocellus. The hind-wings are dark reddish-brown, with several conspicuous black-edged silvery markings, and four yellowish-red spots near the termen. The under side of the female is very much paler.

This butterfly varies considerably on the upper side in the number and size of the ocelli, and in the extent of the reddish-brown markings which surround them; on the under side the silvery spots on the hind-wings are also variable.

The perfect insect has been taken in January and March. It evidently frequents mountains in the South Island, at elevations of about 4,000 feet, but does not appear to be generally distributed in such localities. It seldom settles on the shingle, mostly resting on the snow grass, on which its larva probably feeds. It is a smaller insect than E. pluto, and flies much more feebly. These characteristics will at once enable the collector to distinguish it from E. pluto when on the wing.

Immediately a cloud obscures the sun these butterflies retreat into the tufts of the snow grass, remaining closely hidden there until the sun shines out again. This circumstance makes the capture of the insect, even in a favourable locality, a matter of considerable uncertainty, as bright sunshine is more often the exception than the rule on the summits of high mountains.

Family 3.--LYCÆNIDÆ.

"Anterior legs developed, but tarsi of more or less abbreviated, or with one or both claws absent; posterior tibiæ without middle spurs. Fore-wings with vein 7 absent, 8 and 9 stalked or coincident. Hind-wings without præcostal spur." (Plate I., figs. 15, 16, neuration of Chrysophanus salustius.)

"The family is large and very generally distributed. The species are of moderate size or more often rather small, usually blue, dark brown, or coppery-orange in colouring, often with series of small black pale-ringed spots on lower surface.

{116}"Ovum flattened--spherical or subcylindrical, reticulated and sometimes ribbed, seldom smooth. Larva stout, with few hairs. Pupa attached by tail and a central belt of silk, or sometimes unattached or subterranean."--(Meyrick.)

We have two genera represented in New Zealand, viz.:--

1. CHRYSOPHANUS. 2. LYCÆNA.

Genus 1.--CHRYSOPHANUS, Hb.

"Eyes glabrous. Club of antennæ elongate. Fore-wings with vein 6 separate, 8 and 9 stalked." (Plate I., figs. 15 and 16 neuration of C. salustius).

"An extensive and nearly cosmopolitan genus. Larva short, stout, attenuated at extremities, with short hairs. Pupa attached by the tail and central belt of silk, or sometimes unattached on the ground."--(Meyrick.)

There are three New Zealand species.