List of New Zealand Species of Borkhausenia (Oeco-phoridae: Lepidoptera), including New Species.
[Read before the Nelson Philosophical Society, 11th June, 1924; received by Editor, 16th June, 1924; issued separately, 31st March, 1926.]
It is proposed in the following paper to list all the species of Borkhausenia known to occur in New Zealand, and to give figures of the male genitalia in all instances where the material has been available. The genus is one of the largest in New Zealand, being surpassed only by Scoparia. Including the new forms here described, the total number of species so far discovered amounts to sixty. Many of the forms are obscure, and not easily separated by superficial characters; the study of the male genitalia, however, in great part removes this difficulty.
For the measure of completeness to which I have been able to bring the paper I have to thank several lepidopterists who have freely helped me by supplying material which was lacking in my own collection and that of the Cawthron Institute. To Mr. G. V. Hudson my thanks are especially due, and I have also received valued assistance from Messrs. C. E. Clarke, C. C. Fenwick, E. S. Gourlay, and S. Lindsay. To Messrs. R. Speight and G. Archey, Curator and late Assistant Curator of the Canterbury Museum, I am indebted for the opportunity of examining the members of the genus represented in the Fereday collection. Dr. Tillyard has kindly read over the completed paper and helped me by a full and careful criticism. To all of these gentlemen I desire to express my grateful thanks.
Characters of the Genus.
Borkhausenia Hubner, Verz. bek. Schmett., p. 420, 1826.
I take the definition of the genus from Meyrick as given in the Genera Insectorum, fasc. 180, p. 37, inserting (in square brackets) the notation of the venation according to the Comstock-Needham system.
Head smooth, side-tufts loosely appressed; ocelli posterior; tongue developed. Antennae ¾, in male moderately or rather strongly ciliated (1–3), basal joint moderate, with pecten. Labial palpi moderate or long, curved, ascending, second joint usually nearly reaching base of antennae, with appressed scales, somewhat loose beneath, terminal joint shorter than second, moderate, acute. Maxillary palpi very short, filiform, appressed to tongue. Posterior tibiae clothed with long fine hairs. Forewings with 1b furcate [1A and 2A coalescing near base], 2 [Cu1b] from or near angle, 7 and 8 [R5 and R4] stalked, 7 [R5] to costa, 11 from middle [rf at ½]. Hindwings under 1, elongate-ovate, cilia ⅔–1; 3 and 4 [Cu1a and M3] connate, 5–7 [M2, M1, and Rs] nearly parallel.
Table of the Species.*
B. honorata Philp., Trans. N.Z. Inst., vol. 50, p. 128, 1918.
B. chrysogramma (Meyr.), ibid., vol. 16, p. 44, 1884.
B. compsogramma Meyr., ibid., vol. 52, p. 31, 1920.
B. xanthodesma Philp., ibid., vol. 54, p. 151, 1924.
B. hoplodesma (Meyr.), ibid., vol. 16, p. 44, 1884.
B. loxotis Meyr., Trans. Ent. Soc. Lond., p. 241, 1905.
B. xanthomicta Meyr., Trans. N.Z. Inst., vol. 48, p. 415, 1916.
B. siderodeta (Meyr.), ibid., vol 16, p. 43, 1884.
B. melanamma Meyr., Trans. Ent. Soc. Lond., p. 240, 1905.
B. sabulosa Philp., Trans. N.Z. Inst., vol. 50, p. 128, 1918.
B. paratrimma Meyr., ibid., vol. 42, p. 65, 1910.
B. siderota (Meyr.), ibid., vol. 20, p. 82, 1888.
B. robiginosa (Philp.), ibid., vol. 47, p. 200, 1915.
B. monodonta (Meyr.), ibid., vol. 43, p. 75, 1911.
B. afflicta n. sp. (described below).
B. oxyina (Meyr.), Trans. N.Z. Inst., vol. 16, p. 45, 1884.
B. amiculata n. sp. (described below).
B. aphrontis (Meyr.), Trans. N.Z. Inst., vol. 16, p. 46, 1884.
B. epichalca (Meyr.), Proc. Linn. Soc. N.S.W., vol. 10, p. 793, 1886.
B. maranta (Meyr.), ibid., vol. 10, p. 791, 1886.
B. nycteris (Meyr.), Trans. N.Z. Inst., vol. 22, p. 219, 1890.
B. thalerodes Meyr., ibid., vol. 48, p. 416, 1916.
B. homodoxa (Meyr.), ibid., vol. 16, p. 43, 1884.
B. macarella (Meyr.), ibid., vol. 16, p. 43, 1884.
B. freta n. sp. (described below).
B. anaema (Meyr.), Trans. N.Z. Inst., vol. 16, p. 42, 1884.
B. serena n. sp. (described below).
B. apanthes (Meyr.), Trans. N.Z. Inst., vol. 16, p. 41, 1884.
B. armigerella (Walk.), List Lep. Het. Brit. Mus., vol. 29, p. 698, 1864.
B. pharmactis Meyr., Trans. Ent. Soc. Lond., p. 241, 1905.
B. horaea (Meyr.), Trans. N.Z. Inst., vol. 16. p. 40, 1884.
B. hastata Philp., ibid., vol. 48, p. 422, 1916.
B. apertella (Walk.), List Lep. Het. Brit. Mus., vol. 29, p. 698, 1864.
B. eriphaea Meyr., Trans. N.Z. Inst., vol. 46, p. 107, 1914.
B. phegophylla (Meyr.), ibid., vol. 16, p. 39, 1884.
B. perichlora Meyr., ibid., vol. 39, p. 118, 1907.
B. basella (Walk.), List Lep. Het. Brit. Mus., vol. 28, p. 492, 1863.
B. politis (Meyr.), Trans. N.Z. Inst., vol. 20, p. 81, 1888.
B. pronephela Meyr., ibid., vol. 39, p. 119, 1907.
B. griseata (Butl.), Proc. Zool. Soc. Lond., p. 405, 1877.
B. innotella (Walk.), List Lep. Het. Brit. Mus., vol. 29, p. 652, 1864.
B. brachyacma Meyr., Trans. N.Z. Inst., vol. 41, p. 13, 1909.
B. chloradelpha Meyr., Trans. Ent. Soc. Lond., p. 239, 1905.
B. penthalea Meyr., ibid., p. 239, 1905.
B. amnopis Meyr., Trans. N.Z. Inst., vol. 42, p. 65, 1910.
B. ancogramma Meyr., ibid., vol. 51, p. 352, 1919.
B. opaca n. sp. (described below).
B. hemimochla (Meyr.), Trans. N.Z. Inst., vol. 16, p. 38, 1884.
[Footnote] * Since the completion of this paper Mr. Meylick has described another species, B idiogama (Trans. N.Z. Inst., vol. 55, p. 661, 1924). It appears to belong to the plagiatella group.
B. crotala Meyr., ibid., vol. 47, p. 213, 1915.
B. plagiatella (Walk.), List Lep. Het. Brit. Mus., vol. 28, p. 485, 1863.
B. morosa n. sp. (described below).
B. epimylia (Meyr.), Trans. N.Z. Inst., vol. 16, p. 36, 1884.
B. pallidula Philp., ibid., vol. 55, p. 210, 1924.
B. seclusa Philp., ibid., vol. 53, p. 340, 1921.
B. collitella (Walk.), List Lep. Het. Brit. Mus., vol. 29, p. 655, 1864.
B. chloritis (Meyr.), Trans. N.Z. Inst., vol. 16, p. 36, 1884.
B. letharga (Meyr.), ibid., vol. 16, p. 35, 1884.
B. scholaea (Meyr.), ibid., vol. 16, p. 35, 1884.
B. fenestrata n. sp. (described below).
B. pseudospretella (Stt.), Cat. Brit. Tin., p. 14, 1849.
Notes on the Above List.
Borkhausenia cenchrias Meyr. (Trans. N.Z. Inst., vol. 41,.p. 13, 1909).—This species has been removed to Gymnobathra.
B. asphaltis Meyr. (Trans. N.Z. Inst., vol. 43, p. 65, 1911).—On closer examination this proves to be a Guestia.
B. thranias Meyr. (Trans. Ent. Soc. Lond., p. 240, 1905).—Sunk as a synonym of B. hoplodesma Meyr.
B. siderodeta Meyr.—This is a widely-varying species as regards size, ranging from the very small race (10–11 mm. in wing-expanse), found in Nelson, to the large Stewart Island form, which expands 14–16 mm.
B. chloradelpha Meyr.—I cannot detect any differences between the male genitalia of this and B. perichlora Meyr. The species can be separated only on colour characters, and it seems probable that the two forms represent only the northern and southern varieties of the one species.
B. crotala Meyr.—The genital differences between this and B. plagiatella Walk. are very slight. The prong on the upper angle of the valva in plagiatella is a little more curved round than in crotala, and the uncus differs a little in shape. Series of the two species show constant difference in appearance, though not perhaps more than is observable between series of other species from different localities. On the whole, it seems desirable to separate the two forms, though eventually the distinction may prove to be of no more than varietal value.
Description of New Species.
Borkhausenia afflicta n. sp.
♂. 13½—14½ mm. Head, antennae, and thorax shining dark purplish-fuscous, antennal ciliations in male 3, whorled. Palpi shining dark purplish-fuscous, second segment ochreous within. Abdomen dark fuscous. Legs whitish ochreous, strongly infuscated, tarsi obscurely annulated with ochreous. Forewings moderate, hardly dilated, costa moderately arched, apex rounded, termen hardly rounded, oblique; dark fuscous, slightly purplish; a patch of yellow scales round base of dorsum, sometimes mixed with orange but frequently absent altogether; sometimes a few similar scales on base of costa; from middle of dorsum a band of white to orange scales rises and curves down again to dorsum; frequently there are no markings or only a few coloured scales: fringes dark fuscous. Hindwings dark bronzy-fuscous: fringes dark greyish-fuscous with darker basal line.
♀. 13–15 ½ mm. Head and antennae fuscous mixed with ochreous. Palpi whitish ochreous, outwardly more or less infuscated. Thorax and abdomen bronzy-fuscous. Legs ochreous, anterior pair infuscated. Fore-wings, contour as in male; greyish-fuscous, densely irrorated with yellow, ochreous, and orange, the colour being brightest on and below fold near base; fringes grey-fuscous mixed with ochreous. Hindwings as in male but rather paler.
Differs from B. monodonta (Meyr.) in the less dilated forewings and the shorter antennal ciliations in the male. The markings are usually of much less extent, though both species vary considerably in this regard. The genitalia of the males are very similar, but the lower lobe of the valva is distinctly longer and narrower in B. afflicta.
Abundant in forest during November on the Dun Mountain track, at elevations of from 2,000 ft. to 2,500 ft. Holotype (♂), allotype (♀), and a long series of paratypes in coll. Cawthron Institute.
Borkhausenia amiculata n. sp.
♂. 16 ½–17 ½ mm. Head dark brown. Palpi dark brown mixed with yellow. Antennae dark brown annulated with yellow, ciliations in male 1. Thorax dark brown, tegulae and posterior margin tipped with yellow. Abdomen dark coppery-brown. Legs ochreous mixed with brown, tarsi annulated with ochreous. Forewings moderate, costa moderately arched, apex rather pointed, termen slightly rounded, oblique; dull greyish-ochreous tinged with ferruginous; costal edge at base brown for a short distance, thence yellowish to near apex; a stripe of pale yellow from base of dorsum to tornus, apically attenuated; a small ferruginous spot on upper margin of dorsal stripe at ½; a ferruginous discal spot; an indistinct deeply-excurved ferruginous subterminal line, sometimes obsolcte: fringes ochreous mixed with yellow points. Hindwings coppery-fuscous: fringes fuscous with darker basal line.
Much smaller than B. basella (Walk.), to which it bears considerable resemblance.
Cobb Valley, in December, and Mount Arthur Tableland (4,500 ft.), in the same month. Found among Veronica and other small shrubs. Holotype (♂) and one male paratype in coll. Cawthron Institute.
Borkhausenia freta n. sp.
♂ ♀. 14–15 mm. Head dark greyish-fuscous. Palpi yellow, second segment without and terminal segment strongly infuscated. Antennae greyish-fuscous annulated with yellow. Thorax dark greyish-fuscous, tips of tegulae yellow and a small yellow patch on posterior margin. Abdomen fuscous-grey, brassy-yellow dorsally. Legs pale-yellowish, anterior pair strongly infuscated. Forewing moderate, costa well arched, apex obtuse, termen rounded, oblique; clear yellow, thickly irrorated with dark ochreous on apical half and with a few ochreous scales on basal half; a small area of dark greyish-fuscous on upper half at base, extending for a short distance along costa: fringes concolorous with wing. Hindwings fuscous-grey: fringes grey with an obscure darker basal line.
Near B. macarella (Meyr.), but the dark head and thorax at once distinguish it.
Nelson; common in plantations and about cultivated land from November to January. Holotype (♂), allotype (♀), and a series of paratypes in coll. Cawthron Institute.
Borkhausenia serena n. sp.
♂ ♀. 13–15 mm. Head and palpi whitish-ochreous mixed with brown. Antennae brown annulated with ochreous, ciliations in male ½. Thorax brown, apices of tegulae pale ochreous. Abdomen grey annulated with brown. Legs ochreous, more or less infuscated. Forewings moderate, costa moderately arched, apex rounded, termen very oblique, whitish-ochreous; costa rather broadly brown on basal ⅓; an irregular brown irroration all over wing, usually obsolete on dorsal region at base and beneath and following brown costal basal area; this brown irroration tends to form a spot above dorsum at before ½ and an inwardly-oblique striga from tornus; an angled subterminal brown line faintly indicated: fringes pale ochreous with several rows of dark points. Hindwings greyish-fuscous: fringes grey with an obscure darker basal line.
An obscure species, not closely resembling any other, but nearest to the much larger B. innotella (Walk.).
“Sunnyside” (Waiau); a male and two females taken in bush on a hillside in January. Holotype (♀) and one paratype in coll. A. Philpott.
Borkhausenia opaca n. sp.
♂ ♀. 15–16 mm. Head dark ochreous. Palpi ochreous mixed with fuscous. Antennae dark brown, ciliations in male 2 ½, whorled. Thorax ochreous mixed with dark brown, tips of tegulae whitish. Abdomen dark shining metallic brown on basal segments, median and posterior segments with yellow band followed by whitish margin, anal tuft ochreous mixed with brown. Legs ochreous, more or less infuscated, tarsi annulated with whitish-ochreous. Forewings, costa hardly arched, apex round-pointed, termen almost straight, oblique; ochreous mixed with ferruginous and whitish; a stripe along dorsum more clearly yellow; a suffused ferruginous fascia from costa beyond middle towards dorsum at ½, ending in a blackish spot below fold; a whitish area posterior to this black spot; a dark ferruginous fascia from tornus, coalescing with median fascia below costa: fringes ochreous, mixed with ferruginous basally. Hindwings greyish-fuscous: fringes fuscous-grey with obscure dark basal line.
A pale member of the monodonta group, but the antennal ciliations in the male are much shorter than those of its allies.
Bluff; five specimens, in November and December. Holotype (♂), allotype (♀), and three paratypes in coll. A. Philpott.
Borkhausenia morosa n. sp.
♂ ♀. 13–15 mm. Head and thorax grey. Palpi ochreous, second segment outwardly dark fuscous and terminal segment with fuscous supra-basal ring and irregular markings. Antennae grey. Abdomen fuscous-grey. Legs whitish-ochreous, anterior pairs infuscated. Forewings elongate, costa slightly arched, apex obtuse, termen slightly rounded, oblique; markings very obscure and irregular, frequently absent; a suffused blackish-fuscous fascia from costa at base to above dorsum at ⅓. enclosing the ochreous or yellow plical stigma and usually anteriorly margined with yellowish; an interrupted black or dark-fuscous straight fascia from costa at ½, coalescing with first fascia above dorsum, posteriorly margined with white and including the first discal stigma; an undefined blackish fascia from beyond middle to tornus, usually enclosing some ochreous scales in disc; a white subterminal line interruptedly margined
on both sides with blackish; frequently a considerable irroration of yellowish on apical area: fringes fuscous-grey mixed with blackish. Hind-wings and fringes pale fuscous-grey.
Close to B. crotala Meyr. and B. plagiatella (Walk.), but smaller and darker than either.
Nelson; common in forest from November to February, and taken as high as 3,000 ft. on the Dun Mountain. Holotype (♂), allotype (♀), and a series of paratypes in coll. Cawthron Institute.
Borkhausenia fenestrata n. sp.
♂ ♀. 10 ½–12 mm. Head dull brown, mixed with ochreous posteriorly. Palpi bright ochreous mixed with brown. Antennae brown annulated with ochreous, ciliations in male 2 ½. Thorax bronzy-brown. Abdomen pale bronzy-brown. Legs pale ochreous mixed with brown, tarsi obscurely annulated with paler. Forewings moderate, costa moderately arched, apex obtuse, termen rounded, oblique; pale dull-brown; first discal indicated by a few scattered brownish-black scales; plical obliquely beyond first discal, very small, sometimes consisting of one scale only; second discal larger, lower half white; a very obscure irregular dark-brown subterminal line: fringes dull-brownish mixed with pale ochreous and darker brown. Hindwings bronzy-fuscous: fringes fuscous-grey with darker basal line.
A very obscure but isolated and distinct form; the rather conspicuous parti-coloured second discal is a good specific character.
Dun Mountain, Nelson; fairly common in forest from 2,000 ft. to 3,000 ft. Holotype (♂), allotype (♀), and a series of paratypes in coll. Cawthron Institute.
Key to the Species.*
Owing to the fact that many of the species are very obscurely marked and offer little of a definite nature for characterization, the preparation of a key has been a matter of considerable difficulty. That offered is admittedly imperfect, but may be of use when supported by the study of the full descriptions. The antennal ciliations of the male often offer good distinguishing characters, but I have not thought it advisable to use such as a primary indication of species, as the antennae of the female usually afford no specific distinctions. In the case of several forms, as no specimens exist in New Zealand collections, I have had to rely on descriptions only, and in one instance (B. collitella Walk.), as neither specimen nor description was available to me, I have perforce omitted the species from the table.
|1. Forewings more or less yellow or ochreous||2|
|Forewings not yellow or ochreous||18|
|2. Forewings lanceolate||3|
|Forewings not lanceolate||4|
|3. Wings of normal breadth; forewings with terminal series of blackish dots||hastata.|
|Wings narrow; forewings without terminal series of blackish dots||maranta.|
|4. Costa of forewings margined with fuscous basally||5|
|Costa of forewings not so margined||16|
|5. Basal half of forewings suffused with fuscous||amnopis.|
|Basal half of forewings not so suffused||6|
|6. Head yellow or whitish-ochreous||7|
|Head greyish-fuscous; wing-expanse 14–15 mm.||freta.|
[Footnote] * B. siderota has inadvertently been left out of the key. The species can, however, easily be recognized by its brilliant colour and the leaden-metallic fasciae.
|7. Forewings clear yellow||8|
|Forewings not clear yellow||11|
|8. Forewings with transverse fasciae, sometimes obsolete; wing-expanse 12–13 mm.||hoplodesma.|
|Forewings without transverse fasciae||9|
|9. Fuscous basal margining of costa confined to extreme edge; forewings deep ochreous-yellow||pharmactis.|
|Fuscous basal margining of costa not so confined||10|
|10. Antennae dark fuscous; forewings deep yellow||armigerella.|
|Antennae ochreous-whitish; forewings pale yellow||macarella.|
|11. Fuscous basal margining of costa confined to extreme edge; forewings whitish-ochreous||chlorodelpha.|
|Fuscous basal margining of costa suffused||12|
|12. Head whitish-ochreous mixed with brownish||13|
|Head not mixed with brown||14|
|14. Thorax mostly dark fuscous; forewings pale dull whitish-yellow||chloritis.|
|Forewings mostly light fuscous||15|
|15. Forewings ochreous tinged||horaea.|
|Forewings not ochreous tinged||apanthes.|
|16. Hindwings dark fuscous; forewings yellow, sprinkled with leaden grey||aphrontis.|
|Hindwings not dark fuscous||17|
|17. Forewings deep yellow||apertella.|
|18. Forewings with more or less ferruginous||19|
|Forewings without ferruginous||28|
|19. Forewings deep ferruginous||20|
|Forewings light ferruginous||23|
|20. Forewings with paler dorsal stripe or markings||21|
|Forewings without such markings; wing-expanse 13–15 mm.||oxyina.|
|21. Forewings mixed with grey; wing-expanse 17 mm.||thalerodes.|
|Forewings not mixed with grey||22|
|22. Forewings with dorsal stripe entire; antennal ciliations in male short, 1||basella.|
|Forewings with dorsal stripe interrupted; antennal ciliations in male long, 3||robiginosa.|
|23. Forewings with paler dorsal stripe||24|
|Forewings without dorsal stripe||27|
|24. Head dark-brownish||amiculata.|
|Head ochreous or whitish-ochreous||25|
|25. Hindwings grey-whitish; wing-expanse 20–22 mm.||perichlora.|
|26. Forewings with oblique dark fascia from dorsum; antennal ciliations in male long, nearly 3||opaca.|
|Forewings without such fascia; antennal ciliations in male short, 1 ½||politis.|
|27. Costa of forewings strongly arched||scholaea.|
|Costa of forewings gently arched||eriphaea.|
|28. Forewings dark fuscous||29|
|Forewings not dark fuscous||36|
|29. Dorsum of forewings with complete or interrupted paler stripe||30|
|Dorsum of forewings without such stripe||31|
|30. Forewings with broad yellow subterminal fascia; antennal ciliations in male short, less than 1||honorata.|
|Forewings without such fascia; antennal ciliations in male long, 4 ½||monodonta.|
|31. Forewings with yellow or orange transverse fasciae||32|
|Forewings without such fascia||35|
|32. Forewings with only one transverse fascia||loxotis.|
|Forewings with more than one transverse fascia||33|
[Footnote] * There being no verified example of B. anaema in New Zealand collections, and it being found that no satisfactory character could be selected from the description to separate the species from B. serena, the matter is here left in doubt. Possibly serena is a synonym of anaema.
|33. Forewings with dull-yellow fasciae; number of fasciae 5||xanthodesma.|
|Forewings with bright-yellow or orange fasciae||34|
|34. Forewings with clear golden-yellow fasciae; number of fasciae 4||chrysogramma.|
|Forewings with clear orange-tinted fasciae; number of fasciae 5, third and fourth forming a loop||compsogramma.|
|35. Forewings with oblique whitish fascia from tornus; antennal ciliations in male short, 1||nycteris.|
|Forewings without oblique fascia from tornus; antennal ciliations in male long, 3||afflicta.|
|36. Forewings brownish||37|
|Forewings whitish or grey||49|
|37. Forewings with pale dorsal area||38|
|Forewings without pale dorsal area||40|
|38. Head ochreous-grey; stigmata dark fuscous||ancogramma.|
|39. Wing-expanse 16–17 mm.||pronephela.|
|Wing-expanse 21–22 mm.||phegophylla.|
|40. Forewings narrow, hardly posteriorly dilated||41|
|Forewings broad, posteriorly dilated||46|
|41. Second discal spot conspicuous, partly white; antennal ciliations in male 3||fenestrata.|
|Second discal spot not conspicuous||42|
|42. Forewings with costa bent at ⅓, four obscure oblique fasciae||melanamma.|
|Costa not bent||43|
|43. Head dark fuscous; forewings sprinkled with grey||xanthomicta.|
|Head more or less ochreous||44|
|44. Wings long, 18–25 mm.; stigmata prominent||pseudospretella.|
|Wings short, less than 16 mm.; stigmata obscure or absent||45|
|45. Forewings ochreous-fulvous; hindwings grey||paratrimma.|
|Forewings brownish-ochreous or fuscous; hindwings fuscous||siderodeta.|
|46. Forewings with broad subterminal dark fascia||penthalaea.|
|Forewings without such fascia||47|
|47. Markings almost obsolete||homodoxa.|
|Markings more definite||48|
|48. Terminal segment of palpi short, about half second; forewings less dilated posteriorly||brachyacma.|
|Terminal segment of palpi normal; forewings more dilated posteriorly||innotella.|
|49. Forewings lanceolate, grey||sabulosa.|
|Forewings not lanceolate||50|
|50. Forewings with two widely separated brown fasciae||griseata.|
|Forewings without such fasciae||51|
|51. Head white||52|
|Head not white||53|
|52. Forewings with prominent oblique brownish fascia from base of costa; hindwings fuscous-grey||plagiatella.|
|Forewings without such fascia; hindwings whitish-grey||crotala.|
|53. Head ochreous-white||54|
|Head not ochreous-white||56|
|54. Costa of forewings without dark spots||hemimochla.|
|Costa of forewings with dark spots or blotches||55|
|55. Forewings with terminal series of fuscous dots||pallidula.|
|Forewings without terminal series of dots||letharga.|
|56. Head grey; forewings with ochreous markings||morosa.|
|Head grey; forewings without ochreous markings||57|
|57. Expanse of wing 16–17 mm.; forewings greyer||seclusa.|
|Expanse of wing 11–13 mm.; forewings whiter||epimylia.|
General Description of the Genitalia. (Figs. 7–10.)
The male genitalia in the New Zealand section of the genus are of comparatively simple form, though, for the most part, showing very distinct specific differences. The abdominal segments are rather weakly chitinized, and the inter-segmental membrane between the eighth and ninth is fairly extensive, allowing of the protrusion and withdrawal of the
genitalia. A short description of each structure is now given so as to facilitate the understanding of the figures.
The Ninth Sternite (Ventral Half of the Tegumen).—In many groups of Lepidoptera the ventral part of the sternite (known as the saccus) is produced basally, the plate so formed passing within the preceding segment (see figs. 1 and 2). In Borkhausenia this plate is recurved, the part originally directed basally being so folded back as to project distally above the slight apical projection; this can be seen in any of the lateral views of the genitalia. This saccus is weakly chitinized, especially on the lateral portions. In a few species, such as B. innotella (Walk.), the stronger chitinization extends to the sides (see fig. of B. innotella).
Fig. 1.—Hieroxestis omoscopa Meyr. Lateral view of male genitalia. s, saccus; v, valva; 9t, ninth tergite; 9s, ninth sternite.
Fig. 2.—Hieroxestis omoscopa Meyr. Ventral view of tegumen. s, saccus; 9s, ninth. sternite.
Fig. 3.—Borkhausenia nycteris (Meyr.). Penis. ae, aedeagus; d.e, ductus ejaculatorius; m, manica.
Fig. 4.—Borkhausenia plagiatella (Walk.). Dorsal view of ninth tergite. u, uncus.
Fig. 5.—Borkhausenia basella (Walk.). Female. Lateral view of apical abdominal segments. 7, 8, 9, seventh, eighth, and ninth segments; c.o, copulatory opening; d.b, ductus bursae; i.m, intersegmental membrane; o.o, opening of ovipositor; s.r, segmental rods.
Fig. 6.—Borkhausenia basella (Walk.). Female. Lateral view of abdomen, b.c, bursa copulatrix; c.o, copulatory opening; d.b, ductus bursa.
The Valvae.—The valvae are well developed, broad, and more or less flat. The upper apical angle is generally produced into a downwards-curving process, and sometimes the lower angle bears a similar but smaller process tending to curve upwards. In the siderodeta group the lower process is absent, and the upper takes the form of a short and broad truncated projection. In a few species there is a median process, always small, and in some instances recurved inwardly. On the inner side the lower margin is seen to be folded in, and this folded portion always bears hairs of greater or lesser length and stoutness. The upper arm or process is also usually well armed with hair, but the stout stiff bristles forming the harpes in other groups of Lepidoptera are missing. About the middle of the basal part of the valva there is a longitudinal fold, from the apical portion of which a series of hairs rises. The base of this fold articulates with the juxta, a chitinous plate lying between the valva and supporting the penis.
The Penis.—The penis consists of a large chitinous tube, slightly curved downwards and usually a little swollen at its basal end, a short distance above which the ductus ejaculatorius enters. It is held in place by a membranous sleeve, the manica. Ventrally it is supported by the juxta, this latter structure varying in shape and frequently having some fine hairs on its apical portion. The intromittent organ (the aedeagus) is hard, slightly curved, thin, and pointed. (See fig. 3.)
The Ninth Tergite (Upper Half of Tegumen).—Basally the ninth tergite is deeply indented in the middle, thus forming two large lateral lobes (fig. 4). The gnathos is normally present, frequently showing greater development than the uncus. It is broad at the base, taking up the whole of the breadth of the tergite, but usually tapers to a point which lies between the valvae. In many species there is a projection on the outer surface of the gnathos, usually towards the base. In a few forms the organ is short and the apex outwardly recurved; in B. hoplodesma the gnathos is absent and the uncus is not defined. Between the bases of the gnathos and uncus the anal tube protrudes; this has been figured in only a few instances. The uncus is generally finger-like, occasionally straight, but usually curved or angled downwards; it does not bear an armature of backwardly-directed spines like that often present in other groups of the order. The outer surfaces of the valvae and tegumen are usually clothed more or less with weak hairs; these have been omitted in the figures.
It has not been considered necessary to give more than two drawings of the organs of each species; the first figure shows a lateral view of the structures in situ, and the second represents a valva viewed from within. In all cases the drawings have been made by camera lucida from material macerated in a 10-per-cent. solution of potash prior to mounting the preparation on a slide.
The Female Genitalia.—In the female the eighth and ninth segments are modified to perform the functions of an extensible ovipositor. Normally only a portion of the apices of these segments projects from the abdomen, but complete protrusion of both segments is possible (see figs. 5 and 6). The segmental rods are well developed, those of the ninth segment extending some distance into the seventh segment even when the organ is fully extended. The copulatory opening, which is situated between the seventh and eighth segments, has, in some species, a leaf-like chitinous piece on each side; in others this is absent and a portion of the ductus bursae is itself chitinized. The duct is a long thick tube which, after some convolutions, expands into the comparatively huge bursa copulatrix (fig. 6).
Of the sixty species listed herein I have been able to examine the male genitalia of forty-seven; nine species (macarella, anaema, apanthes, horaea, phegophylla, griseata, collitella, chloritis, and letharga) do not appear to be
represented in New Zealand collections; of sabulosa and hastata only the types are known; of hemimochla I could obtain only the female; and of thalerodes I was not able to obtain a male for dissection, though, through the kindness of Mr. Hudson, I had the opportunity of examining the single male in his collection. As far as could be ascertained without dissection, the genitalia of this form appears to be of the robiginosa type.
A study of the genitalia allows of the grouping of the species into several sections, and such sections agree fairly well with an arrangement founded on superficial resemblance. There are within the larger groups several subgroups; in the following table these have been indicated by the use of a semicolon :—
—Upper angle of the valva produced in a curved process, or prong; the gnathos fairly straight and not recurved at the apex: honorata, paratrimma, epimylia; perichlora, chloradelpha, robiginosa, oxyina, amiculata, opaca, eriphaea; chrysogramma, xanthodesma; ancogramma, politis; pallidula; suderodeta, loxotis: fenestrata; apertella, pharmactis, serena; epichalca.
—Valvae with upper prong only, but gnathos recurved at apex; the recurved portion usually bifid: plagiatella, crotala, amnopis, seclusa, morosa; compsogramma.
—Valvae with both upper and lower prongs: monodonta, afflicta; pronephela, penthalea; basella, innotella, aphrontis. Hoplodesma is a member of the two-pronged group, but is unique in the absence of the gnathos.
—Valvae with a median prong, making three altogether; in such instances the prongs are all short, and may be only rounded prominences; the median one is sometimes recurved, and lies on the inner surface of the valva: brachyacma, homodoxa; freta, armigerella.
—Valvae without prongs, but with the apical portion more or less narrowed; xanthomicta, maranta; melanamma.
Siderota has the apex of the valva armed with small pointed processes; it appears to come nearest to group 3. Nycteris is an isolated form coming under group 1 as to the valvae, but having the gnathos reduced to very small proportions, while the uncus is unusually long. Scholaea is also a form having no close relationship to other species; the short bifid uncus is quite unique. Pseudospretella, as might have been anticipated, shows considerable divergance from the endemic species. The uncus and gnathos are of the normal type of group 1, but the valvae have two internal processes not found in the other species; the dense patch of long fine hair rising from the inner median area is also a unique character. *
Phylogeny of the Species.
In a recent letter to me Mr. Meyrick expresses the opinion that the whole of the New Zealand species of Borkhausenia are the descendants of one immigrant species. Working in accordance with that view, we may postulate a form like hoplodesma as this original immigrant. Here the genitalia are of sufficiently simple type; the valvae are of normal type, though possessing two small prongs; the ninth tergite can hardly be said to bear an uncus, and the gnathos is entirely absent. It is possible, of course, that this apparent simpleness may be the result of specialization, in which case our scheme of descent would be upset completely. Setting this possibility aside for the present, however, it may be useful to build up a tentative phylogenetic scheme, taking hoplodesma as the starting-point. In the following table one name in several instances does duty for a group of species, and it should be remembered that the conclusions reached are not all of the same value, some of them being much more probable than others. The development of the gnathos has been the main guide in the preparation of the tree, modified by the state of the apical portion of the valvae.
[Footnote] * It should be remembered that any reference to “uniqueness” applies to New Zealand species only, and of these only to such as have been available for examination.