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Volume 69, 1940
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Additions to New Zealand Rhyacophilidae—Part 1.

[Read before the Canterbury Branch, July 6, 1938; received by Editor, July 7, 1939; published separately, December, 1939.]

Historical

Rhyacophilidae from New Zealand have been described by R. McLachlan (1866, 1870), R. J. Tillyard (1924) and E. J. Hare (1909). Hare's species, Hydrobiosis ingenua, will never be recognisable, as it was inadequately described and never figured. The type has since been destroyed.* Omitting Hare's species, there are at present eleven species of Rhyacophilidae recorded from New Zealand. Of these, Hydrobiosella stenocera Till. belongs to the Philopotamidae, and Neurochorema decussatum Till. is a synonym for Psilochorema confusum McL., leaving nine valid species. Part 1 of this paper adds eight species, thus bringing the number to seventeen. The matter is of interest as the further additions proposed for Part 2 will, for the time being, easily displace the Sericostomatidae as the dominant family for New Zealand, as regards numbers of species and genera.

General

The synonymy noted above, Psilochorema confusum McL. = Neurochorema decussatum Till., requires further attention. It is not thought advisable at present to sink the genus Neurochorema Till., as it could well serve to receive Ps. confusum McL., which is certainly not congeneric with the genotype, Ps. mimicum McL.

The species here described and those in Part 2, with one exception, are the results of collecting confined, in the main, to the upper Waimakariri River watershed. All, with the exception noted, were obtained by rearing mature pupae in aquaria, during the course of a study of life-histories. Adults of this family are not readily taken in the field.

The figures in this paper, with the exception of those of Costa-chorema brachypter a, are from slide preparations. The Comstock-Needham notation, as modified by Tillyard (1924) has been used for neuration.

I would like to acknowledge with thanks the advice and assistance given me by Mr. M. E. Mosely, of the British Museum, and by Professor E. Percival, of Canterbury University College.

Key to the New Zealand Genera of Rhyacophilidae. (Modified after Tillyard).
1.Forewing with branches of M normally developed.
2.Forewing with M2 and M3 fused basally for some distance, so that an apparent apical fork is formed between them Neurochorema Till.♂♂
2.Forewing with radial cell open. 8

[Footnote] * Letter from Mr. M. E. Mosely, January, 1937.

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Forewing with radial cell present, closed by a cross vein; not symmetrically pointed at apex. 3
3.Radial cell not followed distad by a second small closed cell. 4 Radial cell of forewing followed distad by a second small cell enclosing the wing spot. 7
4.Forewing with both Af1 and Af2 sessile on radial cell. 5 Forewing with either Af1 or Af2 or both stalked from the radial cell. 6
5.Apex of forewing short; forks 1 and 4 absent in hind wing with Sc about half wing length; Sc in forewing running alongside or fused with R1. Hydrochorema Till. Apex of forewing long; forks 1, 2, 3 and 5 present in hindwing; Sc and R1 ending close together in hindwing. Percivalia n.g.
6.Forewing with Af1 sessile on radial cell, Af2 stalked. Hydrobiosis McL. Forewing with Af1 stalked, Af2 sessile on radial cell. Neurochorema Till. ♀♀
7.The small cell distad from the radial cell in forewing is closed distally by the fusion of R4 and R5; veins of distal part of forewing neither close together nor parallel. Synochorema Till. The small cell distad from the radial cell is closed distally by a cross-vein; veins in the distal part close together and parallel. Psilochorema McL.
8.Forewing with apex symmetrically pointed; inferior appendages of ♂ one-jointed. Tiphobiosis Till. Forewing not symmetrical at apex; widest at tornus; inferior appendages of ♂ two-jointed. Costachorema n.g. Note: Hydrobiosella Till. has been omitted from Tillyard's key as it belongs to the Philopotamidae.

Genus Percivalia nov.

Differing from Hydrobiosis McL. in neuration of forewings, in the form of the genital armature and aedeagus, in the abdominal organs of the male, and in having relatively longer and more robust limbs.

Maxillary palpi long and clothed fairly densely with short hair; two basal joints short, together shorter than the third joint which is longest; labial palpi shorter than first three joints of maxillary palpi; mentum bifid, making labial palpi appear four-jointed; ocelli present, small; antennae fine, a little shorter than forewings; wings similar in sexes; forewings narrow, apex acute, pterostigma variably denned, venation normal, forks 1 and 2 in forewing sessile on radial cell, which is short; hindwing with radial cell open and Af4 absent; aedeagus complex, without filum; inferior appendages one-jointed; organs on fifth abdominal sternite of shield type in the female; in the male, pouches between the second and third segments dorsally.

The genus resembles Hydrochorema Till. in neuration, but differs in genitalia, in abdominal organs, and in larvae.

Genotype: P. maxima n.sp.

This genus is dedicated to Professor E. Percival, of Canterbury University College.

Percivalia maxima n.sp. Figures 1, 5, 7, 9, 10.

Expanse: ♂ 33 mm. ♀ 33 mm.

A large insect of golden-brown appearance. Head dark brown clothed on vertex and frons with a shaggy mass of stout, long hairs ranging in different specimens from light golden-brown to blackish-brown;

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eyes black, ocelli ranging from white to yellow; antennae fine, basal joint short and stout, as long as the second and third together, yellowish-brown, ringed with bands of fine dark hair becoming lighter towards the tips; palpi a little finer than the antennae, finely pubescent.

Thorax: prothorax narrow, carrying a dense clothing similar to that on the head; mesothorax having a deep median hollow anteriorly, the lateral ridges with hair like that on the prothorax; tegulae densely covered with similar hair; metathorax lighter in colour, bare; legs pale golden brown, 2, 4, 4, long and strong, fore-legs shorter with darker tarsi; forewings thickly clothed with intermixed light and dark brownish hairs, with strong yellowish to golden-brown upstanding hairs along the veins, particularly in the basal portion; veins yellowish, distinct; fringe, varying shades of brown; hind-wing hyaline, smoky towards the apex, long light hairs on veins in the anal region.

Abdomen in male: sparse hair on lower and posterior edges of tergites, except eighth tergite where the hair-bearing region is two crescentic areas with an incised hairless region between them; posterior margin of seventh sternite with blunt, peg-like tooth; of the eighth with a broad backward extension. The ninth sternite is curved in such a way that the anterior edge is posterior to the posterior edge of the sternite, and from the side appears as a backwardly directed tooth. The posterior margin of the ninth tergite is broken mid-dorsally by a circular excision extending to the anterior margin. From the bay so formed the proctiger rises. Superior appendages, like long, narrow hair brushes rise from the sides of the excision, close to the dorsal margin of the sternite, and bear stout spines on the dorsal surface. Outside these are two lobes with fine hair, and immediately below them are the long twisted intermediate appendages, much longer than other appendages. The inferior appendages are rooted deep in the pit enclosing the genitalia, and curve out and back from their point of origin, their inner surfaces concave, thickly covered with fine hair and shallowly granular in texture; aedeagus dark brown, complicated; the penis curves upward between a pair of claw-like, downward-directed penis guides; para-meres slender, dilated towards the point, which is clawed.

In the female the shield on the fifth sternite ends in a wedge-shaped tooth, less than half as long as the succeeding sternite; sixth sternite bears a shorter and blunter tooth; seventh, or ultimate visible sternite, with rounded posterior margin, notched mid-ventrally.

Holotype ♂, allotype ♀, and series paratypes in Canterbury Museum.

Habitat: small stony streams in beech forest between 1000 and 3000 ft.

Percivalia fusca n.sp. Figures 6, 11, 12.

Expanse: 22 to 25 mm.

Smaller and darker than P. maxima.

Head lass hairy than P. maxima; vertex hairs black with lighter hairs intermixed; lighter hairs predominating on the frons; oculi

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black with light lines and flecks, these probably being post-mortem effects; ocelli small, light; maxillary palpi covered on upper and outer surfaces with dense, fine, fuscous hair; labial palpi with fine light hair; antennae shorter than forewing, fine, dark, clothed in fine blackish hair to the tips.

Thorax less hairy than P. maxima, mesothorax having light hair on the two ridges; legs light yellowish brown in proximal parts, first and second pairs brownish black with bands of yellowish on tibiae and tarsi, third pair light yellowish-brown as far as tarsi, which are lighter than other pairs.

Wings: forewing pterostigma well denned; venation yellowish, strongly defined; surface of wing, with dense fuscous hairs, longer than in P. maxima. From the distal end of the pterostigma, a light crescentic band crosses the wing; several light spots basad from this, marking patches of light hair rising from the veins, which are clad mainly with upstanding fuscous hair; light spots on the margin between the termini of the veins; fringe dense, varying from light to fuscous; hind-wing hyaline, dark smoky effect distally; fringes in anal region, long, light and silky.

Abdomen: female, tooth on fifth sternite as long as succeeding sternite and slightly curved; tooth on sixth short, and blunt; seventh or ultimate visible sternite longer than preceding ones, notched posteriorly; the eighth tergite appears to have no corresponding sternite. Male: long tooth on seventh sternite; eighth sternite short with broadly rounded backward extension, ventrally, of the posterior margin; posterior margin of ninth sternite produced to a point mid-ventrally. Dorsally, the posterior margin of the ninth tergite is excised by a shallow bight about two-thirds of its width, and from this the proctiger rises. F]rom the sides of this excision the club-like superior appendages point downwards and inwards; their ends are pointed and dorsal surface studded with short blunt spines; between the superior and intermediate appendages lies a low wart-like ridge; intermediate appendages, rounded, longer than others; the inferior appendages rise from a cavity and are directed postero-dorsally; they curve in towards the mid-line so that the inner surfaces come to face ventrally at the distal end. Aedeagus, dark brown; penis bifid at point, directed upwards between a pair of hooked guides, which partly surround it near the point; a pair of stout pointed rods rise dorsal to the penis; conspicuous dark brown, rod-like parameres curve from the base, outwards and downwards, and turn up at the points.

Holotype ♂ and allotype ♀ and series of paratypes in Canterbury Museum. Preparations of wings and genitalia in Museum.

Habitat: small rapid streams in beech forest between 2000 and 3000 ft.

Percivalia cassicola n.sp. Figures 2, 13, 14, 15.

Expanse 25 ½ mm.

This insect is very like P. fusca superficially, but is more robust, more uniformly coloured, light spots on wings as in P. fusca being absent, and with denser wing covering.

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Head: antenna not so dark as in P. fusca, becoming lighter towards the rips; covering and colour of head, palpi and thorax much the same as P. fusca.

Forewings densely and evenly covered with fine fuscous hair. Veins with upstanding coarse black hair, interspersed with a few lighter hairs; light spots at both ends of pterostigma, which is well defined; a few white hairs about M.4, opposite the distal end of the pterostigma; a further patch about the hyaline area at the point of bifurcation of Cu.1; no light crescentic band as in P. fusca; fringes short, very small light spots between the termini of veins.

Female adult unknown, but a nymph, which is almost certainly of this species, shows the posterior edge of the terminal sternite as entire, as contrasted with the notched margin of P. fusca; other adult features shown by the nymph did not vary greatly from fusca.

Abdomen in male with a short tooth on the antepenultimate sternite; penultimate tergite very narrow mid-dorsally; ultimate tergite reduced to a stout wire-like ridge, from below which the proetiger rises; ultimate sternite more than twice as long latero-ventrally as it is mid-ventrally; appendages subequal in length; the superior appendages curve downward from a stout base to flatten to a spatulate form in the horizontal plane, and lie between the intermediate and inferior appendages; intermediate appendages long and subcylindrieal; the inferior appendages, viewed from the side, are straight; viewed from below they are seen to taper from a broad base and to have an angular projection on the inner side near the base; aedeagus of the kind figured for the genotype; parameres dark, rod-like, each with an outwardly directed tyne near the point.

Holotype ♂ and two paratypes ♀ in Canterbury Museum. Wings and genitalia mounted.

Habitat as for P. fusca.

Percivalia banksiensis n.sp. Figures 16, 17.

Expanse 24 mm.

This insect is uniformly light golden-brown throughout and conforms closely with the genotype.

Abdomen ♂ short tooth on antepenultimate sternite; penultimate sternite with broadly rounded mid-ventral extension; ultimate sternite drawn out on posterior margin to a blunt peg-like process, thin and almost transparent; viewed laterally the three terminal sternites appear to be toothed; ultimate tergite reduced to a strong ring of chitin, convex posteriorly; posterior margin of penultimate tergite with two tufts of hair widely separated; the under side of the proctiger has a backward-pointing, V-shaped, selerotised band; superior appendages club-shaped from above, dorso-ventrally flattened; inferior appendages broad basally, tapering sharply on the inner side to turn abruptly inwards at the tip; aedeagus of usual type for genus; large brown parameres, somewhat like a red deer's antler, tip turned sharply outward, two outwardly directed tynes at third distance from tip and base respectively, the basal one much the larger; viewed from below the parameres make a double crossing near the tip.

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Holotype, unique ♂ Canterbury Museum Collection; abdomen in balsam.

Taken by A. L. Tonnoir at Hilltop, Banks Peninsula, January, 1925. I have taken what appears to be the larvae of this species in a stream on the Peninsula.

Genus Costachorema nov.

Head broad; eyes large; a large bare groove between eyes and lateral ocelli; maxillary palpi long, the terminal joint the longest; labial palpi very small.

Forewings narrow, acute, fore and hind margins almost straight; neuration dissimilar in sexes; in the male the costal margin folded back dorsally as far as R.1 or less widely, and Sc., which is short, returns to R.1 instead of to C.; in the female the costal fold is absent and Sc. returns to C. normally; venation otherwise similar; forks one to five present; radial and median cells open. Hindwings similar in sexes; fourth cell absent; fairly broad, with fore and hind margins roughly parallel.

Abdomen of female large, with weakly defined shields on fifth sternite; terminal part laterally compressed; male with eversible organs dorsally between second and third segments; genitalia conspicuous; inferior appendages two-jointed; aedeagus complicated, with two or three pairs of appendages distally; no tergite, dorsal to ultimate sternite.

Genotype: Costachorema psaroptera n.sp.

This genus is erected to contain four species of medium to large-sized insects, one of which, C brachyptera n.sp., exhibits abnormal wing development. I have a female of what appears to be a fifth species. It resembles C. xanthoptera n.sp. in general appearance, but has rounded wing tips, and is lighter in colour. Expanse 16 mm., which is very much smaller than any other species of the genus.

Costachorema psaroptera n.sp. Figures 4, 8, 18, 19, 20.

Expanse: male, 30 mm.; female, 30 to 35 mm.

Head: antennae shorter than forewings, basal joint large, inner surface with fine white hair, outer side bare; remainder light yellowish-brown, annulations being indistinct basally, and increasingly fuscous distally; sparse black hairs on occipital ridge; two lines of white hair from the median ocellus backwards; a dense covering on frons of mixed coarse black and white hair; eyes large, dark; ocelli light; maxillary palpi dark, finely pubescent.

Thorax: prothorax narrow, a few long white and black hairs upstanding; mesothorax long, deep chestnut, two lines of long, fine, white hairs anteriorly; metathorax bare, brown; legs, long; hind-legs pale yellowish-brown; middle and forelegs darker on tibiae and tarsi, but yellowish-brown proximally.

Forewings in male folded at anterior margin as far as R.1., fold extending from the base to the pterostigma, which is small, and covering the greater part of Sc. and the humeral veinlet. This fold is opaque and is double; in the male Sc. meets R.1 a little basad from the fork of Rs., and in the female opposite the point of bifurcation

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of R.4 and 5; termen slightly concave; fringe short with light spots at termini of veins; wing semi-transparent, finely mottled greyish effects in the distal half, faintly brownish in the proximal half; a thin white band from the distal end of the pterostigma to Cu.2, roughly parallels the apical margin; a band of black hair from the base of the wing parallel to the posterior margin as far as the junction of A.2 and A.3; from the end of this in the male, to a little beyond the end of A.3, is a white patch with a tuft of white hair, on Cu.2, while in the female this area is light brown with a narrow hyaline line from the terminus of A.3 to the point of bifurcation of Cu.1; veins strongly marked, concolorous with the mottling of the wing, and with sparse, weak, light to white, upstanding hairs; the wing membrane is clothed sparsely with fine hairs, white and darker, and, in the region of the tornus, with occasional reddish hairs; hind wings hyaline with light fringes.

Abdomen dark above and light yellowish-brown below; in the female no tooth on the fifth sternite, a small one on the sixth, and a larger broad tooth on the seventh; part posterior to the seventh segment laterally compressed and no sternites visible; in the male the antepenultimate sternite is toothed; in the penultimate segment the tergite is twice as long as the sternite and wider; posterior margin of terminal tergite is broadly incised, and, from the angle of the incision, is a deep mid-dorsal cleft; the superior appendages are semi-transparent, brown; seen from the side each appears as two very prickly leaves; from below each is like a letter U on a short stalk, the inner side of the U being densely covered with stout brown spines (fig. 20); the chitinous base of the appendages extends on the under side of the proctiger to form a fish-tail; two thin chitinous plates sheathe the distal part of the proctiger ventrally; intermediate appendages fine and clubbed; short hairy appendages at their bases, dorsally; inferior appendages strong, concave on inner surfaces of both joints, with strong spines on the inner edges of the basal joints. The aedeagus is a soft, bulbous organ, the terminal portion of which can be rotated through 180° in the dorso-ventral plane; when fully extended the small pair of terminal appendages take up the middle position; the parameres are bifid from the base, the longer outer portion having a tuft of brown bristles towards the end.

Holotype ♂ allotype ♀ and series of paratypes; and preparations of wings and genitalia in the Canterbury Museum.

Habitat: fast, stony, cold streams in open tussock country from 1000 to 2600 ft. above sea level. Plentiful in suitable streams.

Costachorema xanthoptera n.sp. Figs. 21, 22.

Expanse: 25 to 30 mm. in ♂; 36 to 40 mm. in ♂.

There is a marked disparity in the expanse of the males and females in my collection. A similar disparity exists in the bodies of the sexes, particularly in the abdomens.

Head: hairs on vertex, light yellowish-brown, with a few brown hairs; antennae fuscous, finely and sparsely pilose; palpi as for genus, a little darker than antennae, basal segment of antenna bare on outer surface; eyes large, dark.

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Prothorax small, with hair as on head; mesothorax brown, with scanty hair like that on prothorax; metathorax light brown, bare; legs long and entirely light tawny, except for brown claws.

Forewings: light tawny, semi-transparent, clothed very sparsely with light yellowish to brownish hair; a few darker upstanding hairs on the veins in the anal region; a strong fuscous fringe on the basal part of the costa; light hairs in the fringe opposite the termini of veins; pterostigma small and faintly marked in ♂, large and well marked in the ♂ costal margin in ♀ folded narrowly as far as pterostigma, with subcosta meeting R.1 a short distance basad from the point of forking of the radial sector, but the point of union is variable. Hindwings: hyaline, faintly tawny, fringes light.

Abdomen reddish brown above, lighter below; ♀ with terminal segment laterally compressed; shield on fifth sternite ill-defined; no central teeth, but a small tubercle on the penultimate sternite; posterior margin of ultimate sternite extended midventrally to a broad, blunt point. In the type male, the organs between second and third tergites are everted; a short peg-like tooth on the penultimate sternite; genitalia conspicuous; superior appendages large, bright brown, curving back and up above the proctiger. There is a line of strong spines, beginning near the base, ventrally, and curving to the outside to become dorsal distally. These, together with the dense fringe of hair from the eighth tergite, conceal the genitalia from above in a fresh specimen; the proctiger is long and narrow with two plates ventrally, projecting laterally near the end; intermediate appendages slender, clubbed, with wart dorsally at base; inferior appendages long in basal joint, which is deeply concave on the inner surface; terminal joint short, carried folded inwards; aedeagus brown, strongly chitinized, three pairs of long sharply-hooked terminal appendages; parameres long, rod-like.

Holotype ♂, allotype ♀, and paratypes in the Canterbury Museum.

Habitat: open country gravelly streams, of non-shifting sub-stratum, cold waters; larvae from Glentni (North Canterbury), Kowai River, at east foot of Porter's Pass, and fairly numerous about Mount White bridge, Cass. An adult from the Waimakariri, a tributary of the Waikato, North Island (Prof. Percival).

These insects appear to complete their period of emergence by the end of December. Pre-pupae are again to be found in May.

Costachorema callistum n.sp. Figs. 23, 24.

This insect resembles C. psaroptera in general proportions, but is readily distinguishable by its warmer wing colouring, with a reddish tinge along the posterior margin of the forewing, by the lesser contrast between colour of body and hairy covering, and by the distinct anulations of the antennae, which are visible to the naked eye.

Expanse: 24 mm. ♀.

Head brown, vertex clothed with black hairs interspersed with yellow; frons covered less densely than C. psaroptera, with short yellow and black hairs; max. palpi grey, finely pubescent; labial palpi lighter, short; antennae strongly ringed, fuscous and yellowish-brown; eyes large, dark; ocelli white.

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Prothorax inconspicuous, with long upstanding hairs similar to those on tegulae and mesothorax; legs yellowish-brown proximally, posterior pair with darker bands on tarsi; middle and forelegs strongly landed yellow and dark fuscous on tibiae and tarsi; spurs 2, 4, 4, anterior very small. Wings as for genus, outline like C. psaroptera; but termen not concave. Sc. returns to R.1 opposite point of bifurcation of Rs.; fold in costal margin, narrow, not covering Sc.; dense black fringe proximally on costal margin; wing membrane clothed more densely and with longer hair than in C. psaroptera; white hair of latter replaced by golden; a tuft of black upstanding hair on A.2 between its points of contact with A.3 and A.1; in the cubital region, particularly distally, wine red hair forms the greater part of the wing covering; hindwings hyaline with fuscous fringes.

Abdomen light reddish-brown above, pale yellowish-brown below; hair, dorsally, fine, light, sparse; on terminal tergite, long, golden; no ventral teeth; penultimate sternite much shorter mid-ventrally than laterally; ultimate sternite extending laterally above the plural region; the eighth segment is produced dorsally to a blunt projection; from beneath the sides of this a pair of lightly chitinised triangular plates project; the proctiger is stout and hides from view the superior app. and jedeagus; sup. app. brown, spoon-shaped, the concave surface of the spoon opening downwards, the convex surface fitting into a depression in the soft proctiger; just posterior to the supp. app., a pair of triangular flaps project from the ventral surface of the proctiger; intermed. app. curved and enlarged distally, directed upwards; inf. app. broad in the basal joint, short and dark brown in the terminal joint; both joints concave on the inner surface; aedeagus brown, strongly chitinised, with three appendages terminally, two of which are Looked to point downwards; a long paramere with a slender stem and a broad flat terminal portion is bent up to lie lateral, and adjacent to the sup. app.

Holotype: unique male; in Canterbury Museum; abdomen in balsam. The larva of this species is known to me. The adult probably emerges in the autumn, judging from the condition of larvae collected in mid-summer.

Habitat: Broken River and Cragieburn River, above West Coast road, and Mount Baldy, Cass, at 2600 ft. Cold, stony streams, unstable sub-stratum.

Costachorema brachyptera n.sp. Figs. 3, 25, 26, 27.

A very robust insect, almost black in colour when fresh. Wing abnormality appears to be the rule. Only three females out of a collection of a score of this species are winged genotypically as to shape and size. Expanses of six females were 23, 25, 28, 33, 34, and 35 mm. Ten males were 19, 19, 20, 21, 22, 23, 23, 25, 28 and 29 mm. There is not a corresponding disparity in body sizes within each sex. Wings of short-winged females do not reach the end of the abdomen, but are sub equal in males. The insects, though flightless, are active runners. This species is the largest in the genus.

Head almost black; eyes black; ocelli light, hair on vertex confined to occipital ridge and two small warts; a tuft above the median

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Fig. 1.—Percivalia maxima n.sp. wings ♂. Fig. 2.—Percivalia cassicola n.sp. hind wing ♂. Fig. 3.—Costachorema brachyptera n.sp. wings ♂. Fig. 4.—Costachorema psaroptera n.sp. wings (a), (b) ♂, (c) ♂. Fig. 5.—Percivalia maxima n.sp. aedeagus. Fig. 6.—Percivalia fusca n.sp. aedeagus. Fig. 7.—Percivalia maxima n.sp. (a) labial palpi, (b) maxillary palpi. Fig. 8.—Costa-chorema psaroptera n.sp. head of fresh specimen.

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Fig. 9.—Percivalia maxima n.sp. lateral ♂. Fig. 10.—P. maxima dorsal ♂. Fig. 11.—P. fusca n.sp. dorsal ♂. Fig. 12.—P. fusca n.sp. ventral ♂. Fig. 13.—P. cassicola n.sp. dorsal ♂. Fig. 14.—P. cassicola n.sp. lateral ♂.

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Fig. 15.—Percivalia cassicola n.sp. ventral ♂. Fig. 16.—P. banksiensis n.sp. lateral ♂. Fig. 17.—P. banksiensis n.sp. ventral ♂. Fig. 18.—Costachorema psaroptera n.sp. ventral ♂. Fig. 19.—C. psaroptera n.sp. lateral ♂. Fig. 20.—C. psaroptera n.sp. proctiger from below, showing superior appendages and sclerotised plate C.P. ♂.

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Fig. 21.—Costachorema xanthoptera n.sp. lateral ♂, aedeagus omitted. Fig. 22.—C. xanthoptera n.sp. dorsal ♂, showing tips of inferior appendages. Fig. 23.—C. callistum n.sp. lateral ♂, aedeagus omitted. Fig. 24.—C. callistum n.sp. ventral ♂, aedeagus and other appendages omitted. Tip of proctiger showing. Fig. 25.—C. brachyptera n.sp. lateral ♂. Fig. 26.—C. brachyptera n.sp. dorsal ♂, terminal hooks of aedeagus showing. Fig. 27.—C. brachyptera n.sp. lateral ♂, end of abdomen, dark plate cross-hatched

ocellus and dense hair of frons black, with a few brown hairs intermixed; sides of genae wide and bare; antennae fine, longer than wings of short-winged forms, black, very finely pilose, annulated brown.

Prothorax wider than usual in this family; long hair over the tergum and plurae, black above and lighter at sides, ending just above bases of coxae in a tuft of forwardly directed golden-brown hair; mesothorax dark, glossy brown; a few brown hairs; metathorax light, bare; legs long and robust; coxae brown; anterior surfaces of fore and middle coxae clothed with long brown hair; hind legs and femurs of others, yellowish-brown; tibiae and tarsi of fore and middle legs brown.

Wings vary in form from the somewhat symmetrical type figured to a form like that of the genotype; the holotype shows patches of golden hair, and similar hair in the fringe opposite the termini of veins; the folded costal area in the ♀ is narrow; the forewings of all specimens agree in being semi-transparent, in having venation strongly marked, in being sparsely covered with hair; the fringes are short, dark, and absent from the basal part of the posterior margin; the hindwings are transparent and fairly evenly and sparsely covered with fine black hair, and the fringes short, black.

Abdomen dark brown above, lighter below; ♂ very robust; shields on fifth sternite weakly defined; sixth sternite with a short peg-like tooth, seventh or last visible sternite with posterior margin well defined, brown, and produced mid-ventrally in an obtuse angle; from beneath the margin of the seventh sternite, on each side of the process is a rounded chitinous flap, possibly parts of a much reduced eighth sternite; immediately posterior to the process is a triangular plate, cleft at the apex; laterally, from beneath the sides of the seventh segment, come two hard concave sclerites, chestnut in colour; the terminal part of the abdomen is compressed between these sclerites.

In the ♀ the abdomen is sub-cylindrical and ends abruptly, with very little taper. A short tooth on the antepenultimate sternite; ninth segment apparently incomplete dorsally; proctiger short, broad, with a lobe on each side; inferior appendages large, brown, with darker, club-like styles encircling the genital cavity to meet above the proctiger; intermed. app. small, and directed upward inside the inf. App.; genital cavity deep and large, with dark brown terminal hooks of aedeagus projecting like sister-hooks. In the genital cavity are three pairs of appendages dorsal to the intermed. app. The lowest—blade-like, dark brown, widest at the base—is probably a paramere of the aedeagus; the middle one—short, slender and clubbed—is probably the sup. app.; the upper, which is broad and short, is apparently homologous with the chitinous plates below the proctiger in the genotype (fig. 20, C.P.).

Holotype ♀, allotype ♂ and series of paratypes in Canterbury Museum. Wings and genitalia mounted.

Habitat: Edwards River, in Arthur's Pass National Park, at 3500 feet above sea-level. The stream is very cold and fast, but the substratum not greatly subject to disruption.

Adult insects February to May.

– 340 –

Lettering of Figures

  • A.: Aedeagus.
  • C.P.: Sclerotised plate beneath proctige.
  • G.: Penis guides.
  • I.A.: Intermediate appendage.
  • Inf.A.: Interior appendage.
  • M.: Mentum.
  • P.: Proctiger. An unsclerotised segment (?) carrying the anus.
  • Pm.: Paramere of the aedeagus.
  • Pn.: Penis. The terminal part of the aedeagus.
  • S.A.: Superior appendage.

References

Hare, E. J., 1909. Some Additions to the Perlidae, Neuroptera-Planipennia and Trichoptera of New Zealand, Trans. N.Z. Inst., vol. 42.

Mclachlan, R., 1866. Trans. Ent. Soc. London, Series 3, vol. V.

Mclachlan R., 1870. Some New Forma of Trichopterous Insects from New Zealand; with a list of the Species known to inhabit those Colonies, Journal Linn. Soc., Zoology, vol. X.

Tillyard, R. J., 1924. Studies of New Zealand Trichoptera, Trans. N.Z. Inst., vol. 55.

Tillyard, R. J., 1925. Caddis-Flies (Order Trichoptera) from the Chatham Islands, Records of the Canterbury Museum, vol. 2.

Tillyard, R. J., 1926. Insects of Australia and New Zealand.