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Volume 82, 1954-55
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The Genus Acanthoxyla (Phasmidae)

Abstract

A Revision of the genus Acanthoxyla Uvarov 1944 is given and four new species are described. As the species of this genus have not been illustrated previously a series of photographs of the important diagnostic features is included in four plates.

Acanthoxyla Uvarov, 1944.

1859. Acanthoderus Westwood, Cat. Orth. Ins. Brit. Mus., 1. 48 (pro parte).

1899. Acanthoderus Hutton, Trans. N.Z. Inst, 31: 56 (non Gray 1835).

1904. Macracantha Kirby, Syn. Cat. Orth., 1: 340 (non Simon 1864).

1907. Acanthoderus Brunner, Insektenfam. Phasm.: 183 and 238 (non Gray 1835).

Medium to large sized insects, the female having the head dorsally, and the body both dorsally and ventrally, generally armed with short stout spines and tubercles; the body rounded above and below, with, normally, a pair of lateral foliaceous lobes well developed on Abd. VI and sometimes also on Abds. III, IV, V or VII as well; the operculum reaching, or almost reaching, to the posterior border of Abd. IX and with a prominent spine or tubercle at its base (Figs. 1–2).

In the male, which is only known from the species A. senta, spines are entirely absent from the body, but occasional small tubercles do occur. The genital structures are situated on Abds. VII-IX (Figs. 3–4). The tergum of Abd. IX is extended latero-ventrally with its posterior lateral edges oblique and all its margins thickened; the inner face of the posterior oblique margin, on each side, with a large, heavily chitinized spine (Figs. 3, 5); the dorsal posterior margin indented slightly, heavily clothed with short setae and, on its inner face with a pair of small curved setaceous hooks. Cerci moderately long, well clothed with short fine setae.

The tarsi, in both sexes, five segmented, of which the basal segment is the longest, being 2 to 2.5 times as long as the second or third; the fourth or penultimate segment very short.

Type species for the genus:.Acanthoxyla prasina (Westwood) 1859.

The genus Acanthoxyla includes eight species, all except one of which breed parthenogenetically and, therefore, are known only from females. Except for one species which is normally coloured blue or purple, all the species can occur in either a green or a brown form. These two colour varieties do not intergrade, nor can the green form change to the brown or vice versa. In all species the green variety is much more common than the brown. The spines are usually black and each intersegmental margin is marked by a yellow posterior, transverse dorsal band with a black mid-dorsal dot. The legs are the same colour as the body, with the bases of the fore femora commonly pink or yellowish and the basal joint of each middle and hind femora is often tinged with either pink or ochreous.

Each femur with a large lateral apical spine on each side; the middle and hind femora each with a pair of large ventral, subapical spines one on each latero-ventral

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carina. All femora doubly carinate above and flattened between the carinae, which may be variously armed with blunt spines; ventrally all femora are triply carinate, the central carina unarmed, the latero-ventral carinae, particularly the posterior ventral carina of each fore femur, variously armed with large “plate”-like spines. All tibiae doubly carinate above with the intervening area either flattened or sulcate, a broad expanded lateral carina to each side and a central ventral carina, the lateral and ventral carinae, in each case, usually terminating in an apical spine, so that each tibia has three apical spines, two latero-ventral and one ventral; sometimes, especially on the front legs, these spines may be much reduced in size or even absent. Each carina on the femora and tibiae bears a single row of small stiff setae which give it, superficially, a finely serrated appearance; tarsi with the four basal segments carinate above, sulcate below, the terminal segment rounded above, flattened below, swollen distally and bearing two claws and an arolium, each tarsal segment with an euplantulum below and all segments clothed with very fine short setae. Fore coxae always armed with 1–3 spines, others unarmed. Head prognathous with a prominent transverse ridge between the eyes and a variable number of dorsal spines on the posterior portion.

The antennae are long, consisting of 20–24 segments, of which the basal is expanded laterally and compressed dorsoventrally, being about 2.5 to 3.0 times as long as the second segment, which is stout and usually rounded, though sometimes slightly expanded laterally. The third segment usually twice as long as the second and often having the appearance of being formed from the fusion of two short segments; the fourth segment short, half as long as the third, the remaining segments all long more or less subequal, with the terminal one usually a little longer than the average. Situated dorsally on one of the segments 9–12 there is always a small basal sensory swelling; while each of the species prasina, geisovii, suteri and fasciata have, in addition, on one of the segments 15–17 a larger sensory swelling and the segment on which this is situated is usually foreshortened and kinked providing apparently an important point of flexion on the antenna. All antennal segments evenly clothed, with very short, extremely fine hairs. Prothorax short, about one-quarter the length of the mesothorax; meso and metathorax long, subequal, or the mesothorax a little longer. There is no indication of subdivision of the metathorax and all nine abdominal tergites are visible from above. Paraprocts in the female short, always hidden by the operculum. Prothorax generally showing a narrow, shallow mid-dorsal longitudinal groove and a transverse central “U “-shaped sulcus of variable depth. Generally a suggestion of a longitudinal mid-dorsal line down the remainder of the thorax and abdomen. Prothorax with or without a pair of small, posterior, dorsal spines, the remainder of the trunk variously armed, both dorsally and ventrally, with prominent spines or tubercles according to the species. Always there is a pair of spines or blunt tubercles on the posterior margin of each thoracic and abdominal segment, situated dorsally one on either side of the mid-dorsal line, except sometimes on the prothorax and the terminal abdominal segments. The mesothorax is usually armed ventrally with spines, but this series of ventral spines seldom extends posteriorly on to the metathorax and abdomen, if it does the spines are generally replaced by blunt tubercles which become progressively smaller towards the posterior until they disappear. The abdominal cerci are always large and foliaceous.

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The number and exact positions of the spines on the trunk are not of systematic value, but the zones of the trunk that bear these spines are of systematic value and help to give the clue to the various species that are involved. Similarly the numbers and positions of the spines arming the carinae of the legs are of no systematic value. The ventral spines of the fore femora were used by Hutton as specific characters as also were the numbers of spines on the head and each segment of the thorax, but these characters are too variable to be of specific value. The species of this genus do, however, fall into three distinct groups based on the spination of the body; firstly those without any spines, secondly those with short spines, and thirdly those with long, rather slender, spines.

The eusterna and sternella of the thoracic segments show no features of systematic value in the species belonging to this genus. The sternellum may or may not be armed with spines, and this variation can occur within any one of several of these species.

The basal spine of the operculum is of value systematically, varying from a small tubercle in A. senta (Fig. 21) to a long curved spine in A. suteri (Fig. 1). The length and shape of this spine is reasonably constant, for each species though, occasionally, particularly in the species prasina and geisovii, specimens do occur in which this spine appears abnormal for the particular species.

The genus Acanthoxyla is nearest related to Acanthoderus Gray, from which it is distinguished by the spine at the base of the operculum and the length of the basal tarsal segment, in Acanthoderus the basal segment of the tarsus is shorter than the second or third, whereas in Acanthoxyla it is the longest segment of the tarsus. The genus Acanthoxyla is indigenous to New Zealand, but the species A. prasina has been accidentally introduced to, and established in, England.

During the course of my study of these insects, which has extended over a number of years, I have been assisted by many friends who collected and forwarded specimens to me. To all of these persons I should like to extend my thanks for their help and co-operation and in particular I should like to especially mention Mr. Don Brooker, formerly of Okoke, Taranaki, but now residing in Marton, Mr. E. L. Kehoe, of Greymouth, and Mr. Graeme Ramsay, of Wellington.

In the following descriptions the colours given are the colours displayed by living specimens. These colours change rapidly after death.

Acanthoxyla inermis n.sp. Figs. 18–20.

Length. Body, up to 10.5 cms., antennae to 3 cms.

Colour. Either entirely green or red-brown, the bases of the fore femora deep pink and the posterior segmental borders yellow, with a mid-dorsal black spot; a suggestion of a black mid-dorsal longitudinal line, especially on the prothorax.

Body. Antennae with 23–24 segments and sense organ on 12. Spines and large tubercles entirely absent from head and trunk, the latter with only occasional minute tubercles of the same colour as the insect. Spines of the femora, other than the apical and subapical ones, very small and few in number, or absent. Apical spines on the fore tibiae either minute or absent. Foliaceous lobes absent from the abdomen. Opercula spine a broad, short tubercle (Fig. 20).

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This species, in general appearance, looks very like a large female Clitarchus hookeri but is easily distinguished from that species by the presence of the spine at the base of the operculum.

Localities. Okoke, Taranaki, collected by D. Brooker; Lake Waikaremoana, collected by myself; Nelson, collected by B. W. Hall.

Type and Paratypes. In the Dominion Museum Collections, Paratype also in the author's collection.

Acanthoxyla prasina (Westwood) 1859. Figs. 2 and 10.

Length. Body up to 9 cms., antennae to 2.6 cms.

Colour. Entirely green or brown, with the posterior segmental margins yellow and a yellow lateral longitudinal line on each side of the meso- and metathorax; base of each fore femora rose-pink; inner faces of cerci yellow, spines black.

Body Antennae each of 21–22 segments with sense organs on 12 and 17. A small foliaceous lobe on each side of Abd. V and a large one on each side of Abd. VI. Several short stout black spines and black tubercles present on the head, meso- and metathorax, more particularly on the head and mesothorax; a few small tubercles sometimes occur on Abd. I. Femora all armed with numerous spines along the carinae; the middle and hind tibiae each, usually, with a single rather large proximal “plate”-like spine on the upper surface. Apical spines of fore tibiae present, normal. The sternellum of the prothorax may be armed or unarmed with spines or tubercles. Cerci variable, equal to or much longer than Abd. IX. Opercula spine short and very stout (Fig. 2).

Localities. Found throughout New Zealand. I have collected this species myself from Kaihu, North Auckland; Hutt Valley, Days Bay, Karori and Wilton's Bush, Wellington; Lake Waikaremoana, and from Milford Sound; specimens have been sent to me from Greymouth by E. L. Kehoe; from Bruce Bay by A. B. Keay; from Okoke, by D. Brooker; from Makino, near Feilding, and from Wairongomai by Graeme Ramsay; and from Stokes Valley by J. W. Matthews.

Type. A female in the British Museum (Natural History).

Acanthoxyla intermedia n.sp. Figs. 11 and 14.

Length. Of body, up to 10.2 cms., of antennae to 2.75 cms.

Colour. As in the preceding species, the brown form usually a warm reddish-brown with the lateral longitudinal lines of the meso- and metathorax a paler brown.

Body. Antennae of 22–23 segments with the sense organ on 11 or 12. Foliaceous lobes on Abd. VI only and very small. Spines and tubercles usually black, but sometimes green or brown, corresponding with the body colour. All the spines and tubercles are very small and very few in number: they do not extend beyond the posterior border of the metathorax; there are up to six small spines on the head, 2 to 3 on the mesotergum and 1 to 2 on the metatergum. The spines of the carinae of the femora are also small and few in number, though 4 to 5 may occur on the posterior ventral carina of each fore femur. Apical spines of the fore tibiae are present though small. The abdominal cerci are distinctly longer than Abd. IX. Opercular spine short, stout and straight, but not so stout as that of prasina.

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Fig. 1—Operculum of A suteri side view to show basal spine. Fig. 2—Operculum of A. prasina side view to show basal tubercle; (abdominal terga numbered in small figures) Fig. 3—Male genitalic segments, A. senta from below, note the two large dark spines (s) on the inner margins of tergum IX Fig. 4—Male genitalic segments, A. senta from side. Fig. 5.—Spines of A. huttoni Fig. 6—Spines of A. geisovii. Fig. 7.—Operculum of A. huttoni, side view to show basal spine Scale A-B for Figs. 1 and 2 = 1 mm Scale C-D for Figs. 3 and 4 = 0.5 mm Scale E-F for Figs. 5 and 6 = 1 cm. Scale G-H for Fig. 7 = 1 mm

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Fig. 8.—Acanthoxyla fasciata, specimen from Bruce Bay, abdominal segments indicated in small figures Fig. 9.—Acanthoxyla huttoni, Paratype from Karori with right anterior leg lost at final moult and not regenerated Fig. 10–Acanthoxyla prasina, specimen from Wilton's Bush. Fig. 11–Acanthoxyla intermedia Paratype specimen from Karori with two regenerated hind legs. Scale J-K for Figs. 8–11 = 7 cms.

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Fig. 12—Spines of A suteri Fig. 13.—Spines of A speciosa Fig 14—Operculum of A intermedia, side view to show basal spine Fig. 15—Operculum of A speciosa, side view to show basal spine.Fig. 16—Operculum of A geisoin, side view to show basal spine Scale K-L for Figs. 12–13 = 1 cm Scale M-N for Figs. 14–16 = 1 mm.

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Fig. 17—Acanthoxyla speciosa-type specimen Fig. 18–Acanthoxyla inermis-type specimen Fig. 19—Spines of Acanthoxyla senta. Fig. 20—Operculum of A. inermis. side view to show basal tubercle. Fig. 21.—Operculum of A. senta side view to show basal tubercle (T) Scale O-P for Figs. 17–18 = 3 cms Scale R-S for Fig. 19 = 3 cms Scale U-V for Figs. 20–21 = 1 mm.

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Localities. In private gardens at Karori (Type Locality); also at Johnson's Hill, Karori, collected by myself; Wilton's Bush, collected by myself and Graeme Ramsay; Wairongomai, Wairarapa; Makino; Tauwharenikau Valley; Kilbirnie, Wellington, collected by Graeme Ramsay.

Type and Paratypes. In the Dominion Museum Collections, Paratypes also in the author's collection and in Graeme Ramsay's collection.

Acanthoxyla speciosa n.sp. Figs. 13, 15 and 17.

Length. Body, up to 9 25 cms., antennae to 2.3 cms.

Colour. This is the most strikingly coloured species belonging to the genus Acanthoxyla. The usual form is a purple or violet on the body and legs variously over-mottled or banded with warm brown. Forms occasionally occur, however, in which the ground colour is a pale caerulean blue banded on the legs and mottled on the body with a light warm brown, the bases of the fore femora deep pink with the coxal-femoral joints of the middle and hind legs and all the tibialfemoral joints tinged with the same deep pink. Spines dark brown or black.

Body. Antennae with 22–23 segments, the sense organ on 11 or 12. Foliaceous lobes occur on Abds II–VI, being largest on VI and smallest on II; those of II and III sometimes absent. Spines and tubercles present on the head and thoracic segments where they are moderately large and fairly numerous, the spines short and stout; a few tubercles occur as far back as Abd. III. Spines on the carmae of the femora well developed. A large “plate”-like crest occurs dorso-proximally on each middle and hind tibia. The apical spines of the fore tibiae well developed and sometimes larger than usual. Cerci distinctly longer than Abd. IX. Opercula spine moderately long, slightly attenuated apically, straight but directed slightly to the posterior.

Localities. Karori, Wellington, in gardens, collected by myself (Type Locality); Wilton's Bush, Wellington, collected by myself and Graeme Ramsay; Mungomako Valley, collected by R. J. Ramsay; Nelson, collected by Fereday.

Type and Paratypes. In Dominion Museum Collections; Paratype also in author's collection and Canterbury Museum Collection, Christchurch (Fereday).

Acanthoxyla suteri (Hutton) 1899

1898. Clitarchus geisovii Hutton.

1899. Acanthoderus fasciatus Hutton.

1899. Acanthoderus suteri Hutton.

Figs. 1, 8 and 12.

Length. Body up to 10 cms., usually 8·5 to 9 cms., with the antennae to 2·1 cms.

Colour. Either entirely green or brown as in A. prasina with the bases of the fore femora and other leg joints tinged with red. Spines and tubercles black. Hutton in his original description says this species is pale grey variegated with darker grey, but this may be due to his not having seen his specimen alive.

Body. Antennae with 20–22 segments (19 in the Type) with sense organs on 10 or 11 and 15. Foliaceous lobes occur on Abds. II–VII, though those on II-IV are very small and may sometimes be absent: those on VI are the largest, and others are intermediate. Very heavily clothed, dorsally and ventrally, with relatively thin long black spines and black tubercles which occur from the head to the posterior of the abdomen, though they may be the same colour as the body on

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Abd. IX or, sometimes, absent from this segment. The dorsal and lateral spines of the head and thorax are almost all long and thin, while numerous shorter, ventral spines occur on the meso- and metathorax. Occasional spines and numerous tubercles occur ventrally on the abdominal segments. The spines on the carinae of the femora well developed and numerous; the apical spines of the fore tibiae very small; the middle and hind tibiae each with a large dorso-basal “plate”-like spine. Opercula spine very long, attenuated and strongly curved towards the posterior.

Localities. Morton, near Dunedin (Type Locality); Bruce Bay, South West-land, collected by A. B. Keay, Roding, Nelson, collected by Graeme Ramsay; Roseneath, Wellington, collected by C. Turnbull; Great Barrier Island (the Type of fasciata). The species is probably widely distributed throughout New Zealand, but not of common occurrence.

Mr. R. R. Forster, of the Canterbury Museum, has told me that the Type locality for this species given by Hutton (Trans. N.Z. Inst. 31, p. 57) as Marton, near Wanganui, should be Morton, near Dunedin, and that Hutton had made a note to this effect in that volume of the Transactions in the Canterbury Museum Library.

Type. In the Canterbury Museum, Christchurch; Plesiotype in the Dominion Museum, Wellington.

Remarks. When Hutton described A. suteri he was right in recognising that the spines were relatively longer and thinner than those of geisovii. He failed, however to notice that the spines of his species fasciata are also relatively longer and thinner than those of geisovii and this omission was probably due to the fact that his Type specimen of fasciata was immature. The Type of A. fasciata is in the Canterbury Museum, Christchurch, and is an immature specimen, probably in the penultimate instar, but from my examination of this specimen I am satisfied that it is co-specific with the Type specimen of A. suteri, also in the Canterbury Museum. As suteri has page priority over fasciata this species must now be known by the former name. However, amongst the geisovii-like species I also have noticed certain forms in which the spines are relatively longer and thinner as in suteri, and I consider these constitute a distinct species which I shall name in honour of Hutton and his work on the New Zealand Phasmidae.

Acanthoxyla geisovii (Kaup) 1866

1866. Bacillus geisovii Kaup.

1899. Acanthoderus geisovii Hutton.

Figs. 6 and 16.

Length. Body up to 9.5 cms., antennae to 2.75 cms.

Colour. Either green or brown, as in A. prasina, with the spines and tubercles black. In the green form the top of the head is often suffused with brown; bases of the fore femora a rusty red and the other femoral-coxal joints are tinged with the same colour.

Body. Antennae each with 20–23 segments, sensory organs on 9 to 12 and 15 or 16. Foliaceous lobes occur on Abds IV–VI, those of VI being the largest, those of IV the smallest and sometimes absent. The dorsal spines are very numerous, mostly short, stout and straight with occasional longer ones These spines and tubercles occur from the head down to the posterior border of Abd. V. Ventral spines are numerous on the meso- and metathorax, but no ventral spines

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occur on the abdomen; tubercles do, however, occur ventrally on the anterior abdominal segments. Spines are very numerous and well developed on the carinae of the femora; the apical spines of the fore tibia are large and conspicuous while the tibiae of the middle and hind feet each have a large foliaceous dorsoproximal spine. The abdominal cerci variable, being equal to, slightly longer, or occasionally, much longer than Abd. IX. Opercula spine long, attenuated, straight or faintly curved, and directed slightly towards the posterior.

Localities. Hutton records this species from Great Barrier Island and Canterbury. I have collected it from various localities around Wellington, including Belmont, Karori, Wilton's Bush and Days Bay; also collected by D. Brooker from Okoke; by E. S. Gourlay from Nelson; by E. L. Kehoe from Greymouth, by W. H. Long and D. Spiller, from Auckland; by Miss B. Topp, from Kenepuru Sound; and by myself from Kaihu, North Auckland.

Type. According to Hutton is in the Berlin Museum. A large series of females, including a Plesiotype, is preserved in the collection at the Dominion Museum, Wellington.

Remarks. Hutton records this species as being described from a male, but this is not so. Kaup, in his original description, makes no mention of the sex of his specimen which, from the description, is obviously a female. Hutton apparently took Kaup's mention of a male in the other species B. gerhardii described in the same paper as applying to geisovii also!

Acanthoxyla huttoni n.sp. Figs. 5, 7 and 9.

Length. Body up to 8·5 cms., antennae to 2·25 cms.

Colour. At present known only from green specimens coloured as in A. geisovii and A. prasina with the spines black.

Body. Antennae with 21 segments, sense organs on segments 10 and 15. Foliaceous lobes present on Abds. III–VII, the largest being on VI, those of III, IV and VII always small and sometimes absent. The spines in this species are disposed as in A. geisovii but they are longer and more slender, while many of them are distinctly curved. The cerci are distinctly longer than Abd. IX Opercula spine very long, longer than in geisovii, attenuated, slightly curved towards the posterior (Fig. 7).

Locality. Karori, Wellington (Type Locality). A. huttoni would appear to be rather uncommon and of rare occurrence.

Type and Paratype. In the Dominion Museum, Wellington.

Acanthoxyla senta Salmon, 1948. Figs. 3–4,19 and 21.

This species occurs only on the Three Kings Islands, and is the only species of Acanthoxyla for which a male has been found. It was fully described in my paper on the Orthoptera from the Three Kings Islands, and the following brief note will serve to distinguish it from all the other species of the genus.

Length. Body up to 7.5 cms. in female and 5·6 cms. in male; antennae to 2 cms. in female and 2.25 cms. in male.

Colour. Entirely green in the male, deep chocolate-brown in the female, the posterior segmental margins and the bases of the fore femora yellow; a mid-dorsal broken longitudinal line, white on the pro- and mesothorax, passing into black posteriorly on the metathorax.

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Body. Antennae, in the female with 22–24 segments, sense organ on segment 13; in the male with 22–23 segments and a sense organ on segment 12; the fused third segment almost completely divided into two small segments in both sexes. In the female only the head, meso- and metathorax, Abds. I, II and III both dorsally and laterally with many short, slender, sharp, needle-like spines and numerous small tubercles; ventrally there are tubercles only. In the male the cuticle is almost entirely smooth, there being a few tubercles only on the head and prothorax. Carinae of the femora spined; the apical spines of the fore tibiae present and well developed, the dorso-proximal spines of the middle and hind tibiae absent. Cerci much shorter than Abd. IX, being only about half as long as that segment. Opercula spine reduced to a low, blunt tubercle.

Types. Holotype female and Allotype male in the Auckland Museum Collections; male and female Paratypes in the Dominion Museum Collections.

Systematic Key for the Separation of the Species of Acanthoxyla

1 (14) The spines and tubercles present on the head and body:
2 (10) The spines and tubercles mostly short:
3 (11) The spines and tubercles short and stout:
4 (7) The spines occurring down to the posterior border of metathorax only, though sometimes occasional small tubercles occur on the tergum of Abd. I;
5 (6) The spines and tubercles moderately numerous and quite large A. prasina(Westw.)
6 (5) The spines and tubercles very few in number and very small A intermedia n.sp
7 (4) The spines and tubercles extending further down on to the abdomen;
8 (9) The spines and tubercles moderately large and numerous and extending down to posterior border of Abd. V A geisovii (Kaup).
9 (8) The spines and tubercles small and few in number and extending down to posterior border of Abd. III A speciosa n. sp.
10 (3) The spines short, slender and needle-like A. senta Salm
11 (2) The spines mostly long and attenuated, often slightly curved;
12 (13) The spines and tubercles moderately numerous and extending down to the posterior border of Abd V A. huttoni n. sp.
13 (12) The spines and tubercles very numerous and extending down on to Abd. VIII A suteri (Hutton).
14 (1) Spines and tubercles absent A. inermis n. sp.

References

Uvarov, B. P., 1944. Proc. Roy. Ent. Soc. London (B) 13, pp. 94–96

Westwood,—, 1859. Cat. Orth. Brit Mus., 1, pp. 48–49.

Dr. J. T. Salmon

, F. R. S.N.Z, F.R.E.S.,
Zoology Department,
Victoria University College,
P.O. Box 196, Wellington. N. Z.