Part 35

The expansion of the wings is rather under 1½ inches. The fore-wings are dull yellowish-brown, with many obscure, wavy, transverse, brown lines, which tend to form two ill-defined bands, one rather narrow near the base and the other much broader near the middle of the wing. The hind-wings are very pale yellowish-brown; there are a few obscure dark lines near the dorsum. The veins are distinctly dotted in black, and the outline of all the wings is deeply scalloped.

The perfect insect appears in January, but is not common.

HYDRIOMENA DELTOIDATA, Walk.

(Coremia deltoidata, Walk. 1321. Cidaria inclarata, Walk. 1411. Cidaria perductata, Walk. 1412. Cidaria congressata, Walk. 1412. Cidaria conversata, Walk. 1413. Cidaria descriptata, Walk. 1414. Cidaria bisignata, Walk. 1415. Cidaria aggregata, Walk. 1415. Cidaria congregata, Walk. 1415. Cidaria plagifurcata, Walk. 1416. Coremia pastinaria, Gn., E. M. M. v. 64. Cidaria inopiata, Feld. cxxxii. 3. Cidaria monoliata, Feld. cxxxii. 8. Cidaria perversata, Feld. cxxxii. 14, 24. Scotosia deltoidata, Meyr., Trans. N. Z. Inst. xvi. 70. Cephalissa deltoidata, Meyr., Trans. N. Z. Inst. xviii. 184.)

(Plate VII., figs. 1 to 9 varieties.)

This pretty insect is extremely abundant throughout the country.

The expansion of the wings varies from 1-1/8 to 1-3/8 inches. The fore-wings vary from brownish-black to dull orange-brown; there is a small darker area near the base, then two pale whitish wavy transverse lines, then a broad darker central band, often containing within it a still darker central band, bounded by two wavy black transverse lines; beyond the central band there are nearly always two or three pale brown or whitish, wavy, transverse lines, then an interrupted line just before the termen, and a short oblique whitish line below the apex; there is a black dot a little above the centre of the wing, and a white dot on the termen near the middle. The hind-wings are yellowish-brown, with several wavy, transverse lines near the dorsum; there is a series of fine crescentic black lines on the termen of both fore- and hind-wings.

{48}This species is extremely variable, but may generally be recognised by a careful scrutiny of the above-named characters. One very striking variety occasionally met with has the central band of the fore-wing completely divided in the middle, which thus forms two dark patches, one on the costa, and one on the dorsum. (See Plate VII., figs. 7 and 8.) A further development of this variety, of which I have only seen one example, taken by Mr. Hawthorne at Springfield, Canterbury, and now in his collection, has only the costal patch present, the whole of the lower portions of the band being completely obliterated. (See Plate VII., fig. 9.) The minor varieties are too numerous to specify.

The larva feeds on grasses. When full-grown its length is about 1 inch. The colour is dark brown, with the skin very much wrinkled. It is sluggish in its habits, and lives through the winter, becoming full-grown about the end of September. During severe weather it generally seeks refuge from the elements amongst the stalks and roots of the rank herbage often surrounding stones or fallen logs.

The pupa is concealed in the earth.

The perfect insect appears early in January, and continues in the utmost profusion until the middle or end of March. It may often be seen resting with the wings folded backwards and forming together a triangle, whence the moth has probably derived its name of deltoidata. In the neighbourhood of Wellington I have observed that this insect has very much decreased in numbers during the last ten or fifteen years.

HYDRIOMENA HEMIZONA, Meyr.

(Hydriomena hemizona, Meyr., Trans. Ent. Soc. Lond. 1897, 385.)

(Plate VII., fig. 10.)

This insect has occurred at Terawhiti in the North Island, and at Mount Arthur in the South Island.

The expansion of the wings is about 1-3/8 inches. The fore-wings are blackish-brown, darker towards the apex and termen; there is an obscure rust-red wavy band near the base, and another at three-fourths, considerably bowed towards the termen at the middle; there are also numerous wavy darker lines. The hind-wings are dull grey, and the termen is slightly scalloped.

This species may be distinguished from any of the varieties of H. deltoidata by its narrower wings, and the absence of any distinct central band on the fore-wings.

The perfect insect appears in January. It is a scarce species.

HYDRIOMENA SUBOCHRARIA, Dbld.

(Aspilates (?) subochraria, Dbld., Dieff. N. Z. ii. 285. Camptogramma subochraria, Butl., Cat., pl. iii. 16. Camptogramma strangulata, Gn. x. 423. Camptogramma fuscinata, Gn., E. M. M. v. 92. Arsinoe subochraria, Meyr., Trans. N. Z. Inst. xvi. 73. Anachloris subochraria, Meyr., ib. xviii. 184.)

(Plate VI., figs. 45 and 46 varieties.)

This species is fairly common and generally distributed throughout the country.

The expansion of the wings is about 1¼ inches. The fore-wings are bright ochreous-yellow; there is a brown dot a little above the middle, and a dark brown transverse band at about three-fourths; the termen is shaded with dark brown. The hind-wings are ochreous, with an obscure central transverse line.

A variety (Hydriomena fuscinata, Gn.) often occurs in which the whole of the wings are more or less tinged with purplish-brown (Plate VI., fig. 46).

The perfect insect appears from November till April. It chiefly frequents tussock country and swampy situations. In the Wellington district it is extremely abundant in {49}the clearings at the foot of the Tararua Range. According to Mr. Meyrick the typical form is common in Tasmania and Victoria.

HYDRIOMENA TRIPHRAGMA, Meyr.

(Cidaria triphragma, Meyr., Trans. N. Z. Inst. xvi. 74.)

"Male.--26-27 mm. (about 1 inch). Fore-wings moderate, termen strongly sinuate; pale dull greyish-purple; a very small darker basal patch, outer edge strongly convex, margined by a dark fuscous fascia, posteriorly whitish-edged; a dark fuscous fascia before one-third, irregularly outwards-curved, posteriorly suffused, anteriorly sharply defined and whitish-edged; a minute blackish discal dot; a dark fuscous fascia beyond middle, forming a strong angle in middle, upper and lower halves both inwards-curved, anteriorly suffused, posteriorly sharply defined and whitish-edged. Hind-wings moderate, termen somewhat irregular, projecting in middle; whitish-ochreous mixed with pale purplish; an angulated darker band before middle.