Part 34

The larva, which feeds on the blossoms of the wharangi (Brachyglottis repanda), is pale green with a series of elongate triangular brown markings down the back and an obscure series of brown marks on each side. It may be found during the latter end of October and beginning of November, but is extremely inconspicuous amongst its food-plant. The pupa is concealed in a light cocoon constructed of the remains of the blossoms.

The perfect insect appears from October till February. It frequents dense undergrowth in the forest, and is generally found resting with extended wings on the dark-coloured stems of the kawakawa (Piper excelsum), where it is practically invisible. In this situation its colouring is evidently specially adapted for protective purposes.

{46}Genus 5.--ELVIA, Walk.

"Face smooth. Palpi rather long, straight, porrected, densely rough-scaled above and beneath, terminal joint short. Antennæ in male stout, flattened, bipectinated (2½). Thorax somewhat crested. Fore-wings with vein 6 from a point with 9, 7 from angle of areole, 10 anastomosing moderately with 9, 11 out of 10, running shortly into 12. Hind-wings with veins 6 and 7 stalked, 8 anastomosing with 7 from near base to near transverse vein."--(Meyrick.)

We have one species.

ELVIA GLAUCATA, Walk.

(Elvia glaucata, Walk. 1431; Feld. cxxxii. 25. Elvia donovani, Feld. cxxxii. 5. Elvia glaucata, Meyr., Trans. N. Z. Inst. xvi. 65.)

(Plate VI., fig. 23 and 24 varieties.)

This very pretty insect is generally distributed throughout the country.

The expansion of the wings is about an inch.

The fore-wings vary from pale green to dark steely blue, rarely pale reddish-brown; there is an almost straight, black transverse line near the base; a broad curved line before the middle, shaded towards the termen; then a straight line, breaking up into dots towards the dorsum, followed by a conspicuous cream-coloured blotch near the costa; this again is followed by a fine jagged cream-coloured line; there is a terminal series of black dots. The hind-wings are cream-coloured, tinged with steely blue or green towards the termen; there are a few obscure transverse lines and a short series of dots from the dorsum. The apex of the fore-wing is very blunt, and the termen is slightly hollowed out towards the tornus; the termen of the hind-wings is deeply scalloped.

This species is extremely variable. In addition to the variations above indicated, the markings of many specimens differ considerably in intensity, and there are frequently several large cream-coloured blotches towards the base or middle of the forewings.

The perfect insect appears from September till March, but is not a common species. It frequents forest districts, and may sometimes be found at rest on tree-trunks, where the beautiful colouring of its fore-wings closely imitates that of certain lichens, and renders its detection in such situations extremely difficult. Unlike the insects included in the two preceding genera, this species closes its wings when at rest, the anterior pair alone being visible. These wings are not held flat, but are curiously folded longitudinally, and the end of the abdomen is also curled upwards. By slightly raising the insect above the level of the surrounding surface, this peculiar attitude considerably increases its resemblance to a lichen growing on the stem or branch of a tree. It will also be observed that in this species, which when at rest exposes only its fore-wings, these alone are protectively coloured; whilst in the genera Chloroclystis and Phrissogonus, where both pairs of wings are displayed, both pairs are protectively coloured.

Genus 6.--HYDRIOMENA, Hb.

"Face with somewhat projecting or loose scales, or with conical tuft. Palpi rough-scaled. Antennæ in male ciliated, rarely dentate or naked. Abdomen not crested, or with crests on two basal segments only. Fore-wings with areole double. Hind-wings with 8 anastomosing with cell from near base to beyond middle. (See Plate II., fig. 32 head, figs. 33 and 34 neuration of Hydriomena deltoidata.)

"A very large genus, principally characteristic of temperate regions in both hemispheres.--(Meyrick.)

There are twelve New Zealand species.

{47}HYDRIOMENA GOBIATA, Feld.

(Cidaria gobiata, Feld. cxxxi. 2. Phibalapteryx simulans, Butl., Cist. Ent. ii. 506. Phibalapteryx undulifera, Butl., Cist. Ent. ii. 506. Phibalapteryx anguligera, Butl., Cist. Ent. ii. 507. Phibalapteryx rivularis, Butl., Cist. Ent. ii. 507. Scotosia gobiata, Meyr., Trans. N. Z. Inst. xvi. 70. Cephalissa gobiata, ib. xviii. 184.)

(Plate VI., fig. 43 , 44 .)

This insect has occurred plentifully at Wanganui and Wellington in the North Island, and is generally distributed throughout the South Island.

The expansion of the wings is from 1 to 1¼ inches. All the wings vary from pale ochreous to rather dull yellowish brown, sometimes very slightly tinged with green. There is usually a large number of fine, slightly waved, oblique lines arranged on both pairs of wings, very like the markings in Venusia verriculata (see page 53), both insects evidently having acquired this style of colouring for similar protective purposes. In many specimens the whole of the anterior portion of the fore-wings, a small area at the base of the hind-wings, and a band near the termen are much paler in colour than the rest. There is usually a very oblique elongate pale area near the apex, and an irregular dark spot considerably below the apex. The outline of all the wings is more or less distinctly scalloped.

The larva (according to Mr. Purdie) is about 1 inch in length, greyish-brown, with a rough prominent dorsal tubercle about the ninth segment. There are sometimes other smaller tubercles. It feeds on various species of Coprosoma in January, March, and May.

The perfect insect appears from October till March, and generally frequents rather open country where Manuka and Cabbage Tree Palms are abundant.

HYDRIOMENA PRIONOTA, Meyr.

(Arsinoe prionata, Meyr., Trans. N. Z. Inst. xvi. 73. Anachloris prionata, Meyr., ib. xviii. 184.)

(Plate VI., fig. 47.)

This species has been taken in the South Island at Mount Arthur, Castle Hill and Dunedin.