Described by Mr. Meyrick from the British Museum specimens.
I am unacquainted with this species.
LEUCANIA NULLIFERA, Walk.
(Agrotis nullifera, Walk., Noct. 742; Butl., Voy. Ereb., pl. ix. 5. Alysia specifica, Gn., Ent. Mo. Mag. v. 3. Leucania nullifera, Meyr., Trans. N. Z. Inst. xix. 7.)
(Plate [IV]., fig. 9; head, Plate [II]., fig. 11.)
This large though sombre-looking insect has occurred in the North Island at Taupo and Wellington. In the South Island it has been taken commonly at Mount Arthur, Christchurch, and Rakaia.
The expansion of the wings is from 2½ to 2¾ inches. The fore-wings are uniform dull grey, with a double row of very faint white spots parallel to the termen; the hind-wings, head, thorax, and abdomen are pale grey.
In some specimens the fore-wings are quite destitute of markings, whilst in others the ground colouring varies considerably, and is occasionally dull brown instead of grey.
The larva is very stout, bright yellowish-brown, considerably paler on the under surface; the dorsal line is faintly indicated, the subdorsal and lateral lines are dull brown, with a chain of elongate white spots beneath each; the spiracles and dorsal surface of the posterior segments are black; there are also numerous white dots all over the larva.
This caterpillar feeds on spear-grass (Aciphylla squarrosa), and only a single individual inhabits each clump. It devours the soft, central portions of the tussock, and its presence can generally be detected by a quantity of pale brown "frass," or discoloration, which is generally visible near the bases of the leaves. Owing to the formidable array of spines presented by the spear-grass, this larva can have but few enemies. The presence of these spines makes the insect a difficult one to obtain without special apparatus. A sharp pair of strong scissors, however, will enable the collector to cut off a sufficient number of the "spears" to allow of the insertion of a small trowel or hatchet under the root. The plant can then be lifted out of the ground, and the larva afterwards carefully extracted from its burrow in the stem. These larvæ are full grown about the end of May, which is consequently the best time to obtain them for rearing. The pupa is enclosed in an earthen cell amongst the roots of the spear-grass. The moth appears in November, December, January, February, and March. It is sometimes attracted by light. I have found it commonly on the Tableland of Mount Arthur at elevations of from 3,500 to 4,000 feet above the sea-level, where its food-plant also flourishes.