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Volume 30, 1897
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Art. XX.—The Phasmidæ of New Zealand.

[Read before the Philosophical Institute of Canterbury, 3rd November, 1897.]

The Phasmidæ, known also as “stick-insects” and “leafinsects,” have their head-quarters in the Malay Archipelago, but are spread over all the warm parts of the earth, including Polynesia, as far as Hawaii, Samoa, and Tonga. They are not favourites with collectors, because they take up a large amount of space in the cabinet, and consequently large collections for comparison are not available. Also, they are apt to lose one or more of their legs, which are redeveloped, but of a smaller size, and generally destitute of spines. There are other difficulties connected with their study. None of the New Zealand species have either wings or ocelli, and immature forms can only be distinguished by the imperfect development of their sexual appendages and by their softer integument; while the immature form is known, in some cases, to differ in colour from the adult. Also, the males are comparatively rare, and differ from the females in being more slender and often less spiny than the females. Indeed, the spines on the body and legs are generally variable in both sexes, and the

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best distinguishing characters are the relative lengths of the different parts of the body. It is therefore evident that a considerable amount of observation in the field is necessary before we can decide how many species there are in New Zealand. And this work should be undertaken without delay, for our stick-insects seem to be unable to protect themselves from the introduced birds, and are rapidly becoming scarce in the neighbourhood of the towns.

In this family the first abdominal segment is consolidated with the metanotuin, and is called the median segment.” It forms part of the metathorax, and the first abdominal segment is really the second.

The habitats given to each species are only those known to me. They are merely intended as the commencement of a work which can only be carried out by the united efforts of several observers; but it is hoped that this paper will help to fix the nomenclature, which is the first step in any investigation.

Key to the Genera
Antennæ shorter than the anterior femora, which are not longer than the posterior femora Pachymorpha.
Antennæ as long as the anterior femora, which are longer than the posterior femora—
    Metathorax longer than the middle femora. Clitarchus.
    Metathorax shorter than the middle femora Argosarchus.

Genus Pachymorplia, Gray (1835).

Body scabrous. Antennæ short, considerably shorter than the anterior femora (in the New Zealand species composed of 16–18 joints); first joint large; the second nearly as broad as the first, slightly longer than broad; the third narrower, longer than the second but shorter than the first. Head with two tubercles between the eyes, their bases approximated or continuous. Mesothorax about the length of the middle femora; metathorax shorter. Legs moderate or short, the posterior femora as long as the anterior, the middle and posterior legs with denticulations on the upper edges; tibiæ and first joint of the tarsi simple; tarsi short. Anal styles short, hardly projecting.

♂. Fourth segment of the abdomen longer than broad, not lobate.

♀. Fourth segment of the abdomen longer than broad, with a prominent depressed lobe on each side. Ovipositor not reaching the end of the abdomen.

Distribution. — New Zealand; Australia; Burma; and Africa.

The New Zealand species differ from the others in the body not being tectiform above.

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Pachymorpha hystriculea.

Pachymorpha hystriculea, Westwood, Cat. Orthopterous Insects in the Brit. Mus., part i., p. 16, pl. 1, fig. 4 (1859). Bacillus hystriculea, Hutton, Cat. Orthoptera of New Zealand, p. 75 (1881).

The spines on the body are short and very variable, and the species is best distinguished by the dorsal foliaceous appendage on the third and fourth abdominal segments. It is small on the third but largely developed on the fourth segment. The following are the dimensions of a female specimen in the Canterbury Museum: Length of the body, 53 mm.; of mesothorax, 10 mm.; of metathorax, 9 mm.; of abdomen, 27 mm.; of antennæ, 9 mm.; of anterior femur, 12½ mm.; of middle femur, 11 mm.; of posterior femur, 13 mm.

Hab. Dunedin.

Pachymorpha annulata, sp, nov.

♀. Dark yellowish-brown, with indications of paler transverse bands on the femora. Body rugose with short blunt points, the dorsal surface rounded. Tubercles of the head broadly connected at their bases. Pro- and meso-notum with a pair of short spines near the posterior margin; metanotum with two pairs. The first seven abdominal segments with elevated posterior margins, each armed with a pair of spines, which are largest on the fourth segment. All the femora and tibiæ with blunt denticulations above; the middle and hind femora with three larger denticulations below, a pair near the distal end and a single one near the middle. Supraanal plate slightly emarginate at the apex. Ovipositor keeled, rounded at the apex. Length of the body, 49 mm.; of mesothorax, 9½ mm.; of metathorax, 8 mm.; of abdomen, 26 mm.; of antennæ, 10 mm.; of anterior femur, 12½ mm.; of middle femur, 11 mm.; of posterior femur, 13 mm.

Hab. Dunedin.

This species is not so spiny as P. hystriculea, and the denticulations on the legs are blunter. But its distinguishing characters are the elevated posterior margins of the abdominal segments.

Genus Clitarchus, Stål. (1875).

Antennæ slender, about as long as the anterior femora, 20–22-jointed; first joint large, contracted towards the base; second joint narrower, subquadrate; third joint longer than the second but shorter than the first. Head with a keel on each side between the eyes and the bases of the antennæ. Pronotum with a transverse impression near the middle. Metathorax nearly as long as the mesothorax. First segment of the abdomen longer than broad. Legs medium, the middle

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femora not longer than the metathorax; margins of the femora generally dentate throughout most of their length, the posterior armed with a tooth near the apex. First joint of the tarsi rather long, tectiform above. Anal styles foliaceous, elongated.

♂. Abdominal segments dilated at the ends; the last compressed, its sides deflexed and expanding posteriorly.

♀. Ovipositor reaching the apex of the abdomen; subcymbiform, gradually narrowed posteriorly.

Distribution.—New Zealand only.

Section A.

Body smooth. First joint of the anterior tarsi longer than the others together. First segment of the abdomen much longer than broad. No spine on the ovipositor. Anal styles narrow.

Clitarchus hookeri.

Bacillus hookeri: White, Zool. Voy. “Erebus” and “Terror,” Insects, p. 24, pl. 6, fig. 6 (1846). Westwood, Gat. Orthopterous Insects in Brit. Mus., part i., p. 14 (1859). Hutton, Cat. Orthoptera of New Zealand, p. 74 (1881). Clitarchus hookeri, Stål., Recensio Orthopterorum, part iii., p. 83 (1875). Phasma hookeri, Butler, in Zool. Voy. “Erebus” and “Terror,” Insects, p. 24 (1874).

Hab. North Island and Canterbury.

In this species all the femora are serrated, more strongly in the female than in the male.

Clitarchus coloreus.

Bacillus coloreus, Colenso, Trans. N.Z. Inst., vol. xvii., p. 151 (1885).

This species is closely allied to C. hookeri, but Mr. Colenso says it is very distinct, owing to its many and bright colours, as well as the configuration of the head and anterior femora.

Hab. Hawke's Bay.

Clitarchus læviusculus.

Clitarchus læviusculus, Stål., Recensio Orthopterorum, part iii., p. 82 (1875).

♀ “Pale-greenish, ornamented with a black dorsal line (in the example described it can be distinguished on the pronotum, on the bases of the other thoracic segments, and on the apices of the abdominal segments). Antennæ toward their apices and the bases of the anterior femora lightly tinged with rose-pink. Femora slender, the posterior pair below armed with an acute tooth near the apex on the mar-

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gin. Length of the body, 83 mm.; of thorax, 36 mm.; of mesothorax, 16 mm.; of metathorax, 16 mm.; of abdomen, 42 mm.; of anterior femur, 20 mm.; of middle femur, 13 mm.; of posterior femur, 18 mm. Width of the mosothorax, 3 mm.” (Stål.)

Hab. Canterbury½

This species differs from C. hopkeri in having the legs more slender and quite unarmed, except the subapical teeth of the posterior femora. The head has two slight tubercles at its base in the middle.

Section B.

Thorax spined. First joint of the anterior tarsi not longer than the others together. First segment of the abdomen subquadrate. A spine near the base of the ovipositor. Anal styles broad.

1. A protuberance between the eyes.

Clitarchus spiniger.

Acanthoderus spiniger: White, Zool. Voy. “Erebus” and “Terror,” Insects, p. 24 (1846). Westwood, Cat. Orthopterous Insects in Brit. Mus., p. 48 (1859). Hutton, Cat. Orthoptera of New Zealand, p. 76 (1881).

Described from a single male specimen collected by Dr. Sinclair.

Hab. Auckland (?).

Clitarchus atro-articulus.

Bacillus atro-articulus, Colenso, Trans. N.Z. Inst., vol. xvii., p. 154 (1885).

Hab. Hawke's Bay.

Described from a single female specimen. Perhaps it is the female of the last species.

2. No protuberance between the eyes.

Clitarchus prasinus.

Acanthoderus prasinus: Westwood, Cat. Orthopterous Insects in the Brit. Mus., part i., p. 49, pi. iii., fig. 2 (1859). Hutton, Cat. Orthoptera of New Zealand, p. 77 (1881).

Described from a female collected by Sir G. Grey.

Hab. Auckland and Canterbury.

Clitarchus filiformis.

Bacillus filiformis, Colenso, Trans. N.Z. Inst., vol. xvii., p. 153 (1885).

Hab. Hawke's Bay.

Probably the male of the last species.

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Clitarchus geisovii.

Bacillus geisovii: Kaup., Pro. Zool. Soc. of London, 1866, p. 578. Hutton, Cat. Orthoptera of New Zealand, p. 75 (1881).

This species is easily distinguished from C. prasinus by having the abdominal segments strongly spined above. The type, which is in the Berlin Museum, is a male. The following is a description of two females in the Canterbury Museum, which I believe to belong to the same species:—

Pale-green (turning brown when dry), with strong black spines. Head with about eight spines, of which two pairs are on the vertex. Prothorax with one to three pairs of spines above and two spines on each side, smooth below. Meso-thorax and metathorax with numerous strong spines above and on the sides, and a few below. The first four or five abdominal segments with strong spines above, nearly smooth below, the posterior segments with only a pair of spines. The fourth, fifth, and sixth segments have lateral lobes, those of the sixth segment being the largest. Anterior coxæ with strong spines; anterior femora with one row of spines below and slightly serrated above; middle and posterior femora with two rows of spines below and two above. Anterior tibiæ unarmed; middle and posterior tibiæ with a single proximal denticulation above. Supra-anal plate squarely truncated at the apex. Length of the body, 78 mm.; of the mesothorax, 15 mm.; of metathorax, 14 mm.; of abdomen, 42 mm.; of antennæ, 19 mm.; of anterior femur, 19 mm; of middle femur, 12½ mm.; of posterior femur, 15 mm.

Hab. Marton, near Wanganui.

Genus Argosarchus, gen. nov.

Allied to Clitarchus, but differing in the following characters: The spines on the body are more slender, and sharper. Antennæ 23-jointed; first joint with parallel sides; the second longer than broad; the third elongated, longer than the first. Metathorax considerably shorter than the mesothorax; not longer than the middle femora. Basal joints of the middle and posterior tarsi crested. Anal styles much shorter than in Clitarchus. Median segment shorter than the metanotum Tibiæ below carinate to the apex. Anal styles flattened.

Distribution.—New Zealand only.

Argosarchus horridus.

Acanthoderus horridus: White, Zool. Voy. “Erebus” and “Terror,” Insects, p. 24, pl. 5, fig. 4 (1846). West-wood, Cat. Orthopterous Insects in Brit. Mus., p. 49

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(1859). Hutton, Cat. Orthoptera of New Zealand, p. 76 (1881).

Hab. Auckland (?); Canterbury.

Argosarchus gerhardii.

Bacillus gerhardii: Kaup., Pro. Zool. Soc. of London, 1866, p. 577. Hutton, Cat. Orthoptera of New Zealand, p. 75 (1881).

This species is distinguished from the last by its smooth head and pronotum, but I believe it to be only a variety, as I have several intermediate forms. The following are the dimensions of the largest female in the Museum collection: Length of the body, 152 mm.; of the mesothorax, 32 mm.; of the metathorax, 24 mm.; of the abdomen, 80 mm.; of the antennæ, 38 mm.; of the anterior femur, 37 mm.; of the middle femur, 23½ mm.; of the posterior femur, 31 mm. The colour is generally brown or grey, and in the female lateral lobes are sometimes present on the fourth and sixth abdominal segments, but more often they are absent.

Hab. Southland; Canterbury.

Argosarchus sylvaticus.

Bacillus sylvaticus, Colenso, Trans. N.Z. Inst., vol. xiv., p. 278 (1882).

Hab. Hawke's Bay.

This species has no spines on the head; but the pronotum is said to have three longitudinal rows of large distant spines, 3–4 in each row, and the prosternum is said to be very spiny, with long sharp spines. Perhaps there is some error in the description; and, if so, it will have to be united with the last species.

Incertæ sedis.

Bacillus minimus, Colenso, Trans. N.Z. Inst., vol. xvii., p. 153 (1885).

Hab. Hawke's Bay.

The description is not sufficient to enable me to make out the genus to which this belongs. Mr. Colenso says that it is adult, but the reasons he gives for so thinking—viz., “its fully-developed antennæ,” &c.—are not very convincing.