Part 58

SELIDOSEMA HUMILLIMA, n. sp.

(Plate IX., fig. 5.)

This inconspicuous-looking insect has occurred at Wellington.

The expansion of the wings of the male is about 1-1/8 inches. The fore-wings are dull yellowish-brown; there are three short oblique dark brown stripes on the costa, inclined very much towards the termen; the first of these stripes is distinctly double, and the second and third partially so; there is an indistinct brown mark just below the apex, several slender faint streaks on the veins near the middle of the wing, and a very distinct brown shading on the dorsum. The hind-wings are very pale ochreous.

This species may be readily distinguished from the other species of the genus by its small size and by the obliquity of the costal stripes. In S. humillima the costal markings slope very rapidly from the base towards the termen; in the {84}other allied species these markings are but slightly inclined, and in some cases slope in the reverse direction.

The perfect insect appears from December till March. It frequents the immediate neighbourhood of Wellington, but is not a common species. At present I am only acquainted with the male insect.

SELIDOSEMA PRODUCTATA, Walk.

(Larentia productata, Walk. 1197 (?). Selidosema pungata, Feld. cxxxi. 23. Selidosema (?) fragosata, Feld. cxxxi. 29. Zylobara productata, Meyr., Trans. N. Z. Inst. xvi. 98.)

(Plate IX., figs. 6, 7, 8, 9, and 10 varieties, 11, 12, 13, and 14 ditto; Plate III., fig. 22, larva.)

This species is very common, and generally distributed throughout both the North and South Islands. It has also occurred at Stewart Island.

The expansion of the wings of the male is 1-3/8 inches, of the female 1-1/8 inches.

The fore-wings vary from pale yellowish-brown to rich chocolate-brown; there are two curved transverse lines near the base, generally enclosing a paler stripe between them; next a broad dark central area; then a wavy paler transverse line, usually followed by a very much paler irregular band, generally formed by two partially disconnected patches, one on the costa and one on the dorsum; there is a jagged, whitish, transverse line near the termen, always broken in the middle, and often shaded with black towards the base of the wing. The hind-wings are ochreous, speckled with brown towards the dorsum; there is usually a brown central dot.

This is an extremely variable insect. In some specimens there are very extensive white patches on the wings, whilst in others the colouring is almost uniform rich brown, and the characteristic markings can only be detected with difficulty. It may, however, be distinguished from the allied species by the interrupted pale jagged transverse line near the termen and by the absence of greenish colouring.

The eggs are oval with the surface honeycombed; they are pale green in colour.

The young larva, when first hatched, is much attenuated, light reddish-brown with a broad pale lateral stripe, and a few bristles. The full-grown larva measures about 1½ inches in length; it is rather slender and has a large hump on the sixth segment. Its colour is dark reddish-brown, mottled and striped with dull white and greenish.

It feeds on the white rata (Metrosideros scandens). During the day it firmly grasps a stem of its food-plant with its prolegs, holding the rest of its body out from the branch in a perfectly straight and rigid position. When in this attitude it so exactly resembles a twig, that, even in the case of captive specimens, it is often a matter of the greatest difficulty to find a caterpillar amongst the branches. Several times I have even caught hold of a larva, thinking it to be a twig, so perfect is the resemblance. At night these larvæ become much more active, and by the aid of a lantern they may then be seen busily walking about and feeding.

The pupa is enclosed in a slight cocoon about two inches below the surface of the earth. The larvæ of the autumnal brood remain in this condition during the winter, but in the case of the spring and summer broods the pupa state only occupies a few weeks.

The moth appears from November till May. It is very common in forest regions, and may be observed resting on the trunks of the trees, its pale yellow hind-wings being completely concealed by the mottled brown fore-wings. In this position the insect is almost invisible, and the protection afforded by its colouring is at once apparent. In the autumn evenings it is often very abundant at the blossoms of the white rata.

{85}SELIDOSEMA ARISTARCHA, Meyr.

(Selidosema aristarcha, Meyr., Trans. N. Z. Inst. xxiv. 216.)

(Plate IX., fig. 17 , 18 ; Plate III., fig. 17, larva.)

Of this fine species only about a dozen specimens have hitherto been captured, all of which have occurred in the immediate vicinity of Wellington. It is consequently at present a rarity, but future collectors will probably find the insect in many other parts of the country.

The expansion of the wings varies from 1¼ to 1½ inches. The fore-wings are light ochreous-brown; there is a small white-edged brown spot near the base; two oblique curved brown transverse lines enclosing between them a white space towards the dorsum; a short stripe on the costa, near the middle, edged with white towards the base of the wing; a doubly curved transverse line beyond the middle, finely edged with white towards the base of the wing; there is also a short white-edged brown stripe extending from the apex of the wing to the last-named transverse line, the two lines enclosing between them a small pale triangular area; there are five short longitudinal brown lines running from the termen to the outermost of the transverse lines, two of them being tipped with white towards the base of the wing. The hind-wings are dull ochreous-brown, with two very faint brown transverse lines towards the dorsum, and several whitish spots and one brown spot near the tornus. The female is a little darker in colour than the male.

This insect varies slightly in size.

The larva feeds on Cyathea dealbata (tree-fern) in September. Its colour is dull reddish-brown with an irregular brownish-black blotch on the side of each segment, and a dark brown dorsal line. It is very sluggish in its habits.

The pupa is concealed amongst moss, &c., on the surface of the ground, the insect remaining in this state for about six weeks.

The moth appears from September till March, and frequents dense forests. It has been dislodged from its food-plant in the daytime, and has also been taken on the flowers of the white rata in the evening.

SELIDOSEMA MELINATA, Feld.