The Genitalia of the Genus Gymnobathra (Oecophoridae: Lepidoptera).
[Read before the Nelson Philosophical Society, 23rd November, 1925; received by Editor, 9th December, 1925; issued separately, 19th February, 1927.]
The genus Gymnobathra was created by Meyrick in 1884, the type being flavidella Walker. Sixteen species have been described, of which a list is here given.
Gymnobathra philadelpha Meyr., Trans. N.Z. Inst., vol. 16, p. 33.
Gymnobathra hyetodes Meyr., ibid., vol. 16, p. 32.
Gymnobathra habropis Meyr., ibid., vol. 20, p. 80.
Gymnobathra hamatella (Walk.), Cat. Het., vol. 29, p. 700; Meyrick, Trans. N.Z. Inst., vol. 16, p. 31.
Gymnobathra flavidella (Walk.), Cat. Het., vol. 29, p. 665; Meyrick, Trans. N.Z. Inst., vol. 16, p. 31.
Gymnobathra sarcoxantha Meyr., Trans. N.Z. Inst., vol. 16, p. 29.
Gymnobathra coarctatella (Walk.), Cat. Het., vol. 29, p. 768; Meyrick, Trans. N.Z. Inst., vol. 16, p. 28.
Gymnobathra squamea Philp., Trans. N.Z. Inst., vol. 47, p. 200.
Gymnobathra parca (Butl.), Proc. Zool. Soc. Lond., 1887, p. 405; Meyrick, Trans. N.Z. Inst., vol. 16, p. 29.
Gymnobathra calliploca Meyr., Trans. N.Z. Inst., vol. 16, p. 30.
Gymnobathra bryaula Meyr., Trans. Ent. Soc. Lond., 1905, 238.
Gymnobathra thetodes Meyr., ibid., 1901, 574.
Gymnobathra cenchrias (Meyr.), Trans. N.Z. Inst., vol. 41, p. 13.
Gymnobathra tholodella Meyr., ibid., vol. 16, p. 30.
Gymnobathra omphalota Meyr., ibid., vol. 20, p. 81.
Gymnobathra caliginosa n. sp. This volume.
Of the above sixteen species three, philadelphia Meyr., thetodes Meyr., and sarcoxantha Meyr., do not appear to have been recognised since their description in 1883. Two specimens of sarcoxantha, a male and a female, are in the Fereday collection at the Canterbury Museum, and through the courtesy of the Curator I have been able to examine these. They bear the date “1884” but have no locality label. The male I should certainly put down as belonging to the pale race of G. coarctatella. As far as can be ascertained from the dry specimen the genitalia do not differ from that species. The female has aborted hindwings, they being only about half as wide as the normal. Otherwise there is nothing to distinguish the specimen from coarctatella, and I have little hesitation in regarding it as merely an aberrant specimen of that species. G. philadelpha is represented in the same collection by four specimens, two of each sex, a label in Fereday's handwriting being pinned beside them. This label reads, “10/1/79, Mount Hut, bush gully north of Conical Hill.” As the month and locality agree with those given for the type it is probable that these specimens represent part of the material taken at the same
time. But the specimens appear to me to belong to G. habropis Meyr.; there is no difference in the male genitalia.
In view of the number of figures which have been prepared it will not be necessary to deal with each species in detail; it will be sufficient to give a general description of the organs, pointing out marked specific differences.
General Characters of The Male Genitalia.
The Tegumen.—The tegumen in Gymnobathra is a well developed organ. Its lateral arms, which are rather narrow, are loosely attached to the apices of the vinculum and its dorsal apex is produced into a definite uncus. Viewed laterally the uncus does not seem to vary much, except in the matter of proportionate length, but a dorsal view reveals a very great diversity of shape. In tholodella it is short, narrow and spine-like; in squamea it is short and pointed but very broad basally; in parca and flavidella longer and finger-like; in hamatella, hyetodes, habropis, omphalota, caliginosa and cenchrias similar, but slightly spatulate; in calliploca deeply constricted basally and widely expanded apically. G. bryaula exhibits a very unusual uncus. It is sharply angled downwards at about half its length and its apex is expanded and truncated, forming an almost circular flat disc.
The Gnathos.—The gnathos is a chitinized band rising from both sides of the tegumen near the base of the uncus, and forming a half-hoop to support the anal tube. It may be directed downwards at right angles to the tegumen or obliquely backwards or forwards. In some species, as squamea, it is a simple half-hoop, in others, as omphalota, the sides are straightened and meet in a central point, this point being often produced into an upturned hook. G. calliploca has a most unusual gnathos. The arms do not approach each other, and the apex is formed by a straight broad cross-piece, the forward edge of which is clothed with short dense hair; the whole apparatus may be described as scoop-like.
The Vinculum.—The vinculum is small in Gymnobathra, reaching its greatest length in development in omphalota, habropis, hyetodes, and hamatella. The arms are thin, and frequently taper to a point; the basal plate may project forwards and backwards, or in one direction only.
The Aedeagus.—The aedeagus is usually short and stout, more or less curved, and with some spines within near the apex. In tholodella the organ is elongate and thin. Close to its apex and rectangularly projecting is a conical process, a feature not found in any of the other species.
The Juxta.—The juxta in this genus exhibits considerable variety of form. The most general feature is the presence of a pair of lobes, usually with some short hairs towards the apices. These lobes may be short and stout or thin and elongate; in several species there are a pair of chitinized plates between them, which, in more than one species curve round apically and almost encircle the aedeagus (see figures of squamea and coarctatella).
The Harpes.—The most general feature of the harpes in Gymnobathra is the development of the basal portion of the ventral margin into a separate lobe or process. In calliploca this is seen in its simplest form. A portion of the basal margin is folded in, and this fold has
become a free cone for a short distance at its apex. The fold, with its free apex, can be seen gradually extending in length through other species while the apex tends to turn inwards. In tholodella the free' apical portion reaches almost across the harpe, and a still further lengthening has occurred in parca and coarctatella. In the latter two species a small process has developed beneath the long one; in parca this is thin and pointed and in coarctatella it is broad and obtuse. In two species, cenchrias and caliginosa, the basal ventral portion of the harpe forms a separate lobe, being divided from the main portion by a deep fissure which reaches almost to the base of the organ. On the inner surface of the harpe there is usually a fairly dense clothing of fine long hair on the apical half directed obliquely backwards towards the dorsal margin, coarser hairs being generally found scattered about the other parts. G. squamea is peculiar in having the outer surface of the harpe clothed with elongate scales, and in G. bryaula a patch of similar scales occurs on the disc of the inner surface.
The Female Genitalia.
In the normal position, all but the hairy apical half of the ninth segment is retracted within the eighth, the eighth being also partly telescoped within the seventh. When extended it is seen that the intersegmental membrane between the eighth and ninth segments is almost as long as the ninth segment, thus allowing of considerable elongation when the deposition of ova is taking place. The copulatory opening (ostium) is placed basad of the middle of the eighth segment. The ductus bursae is fairly strongly chitinized for a short distance from its commencement, the bladder-like bursa copulatrix being well differentiated from the duct.
Key to The Species of Gymnobathra Based on The Characters of The Male Genitalia.
|1.||Apex of dorsal lobe of harpes extending beyond costa||2.|
|Apex of dorsal lobe of harpes not extending beyond costa||3.|
|2.||Second process of lobe narrow and pointed||parca.|
|Second process of lobe broad and apically dilated||coarctatella.|
|3.||Apex of dorsal lobe extending to costa of harpe||tholodella.|
|Apex of dorsal lobe extending to costa of harpe||4.|
|4.||Apex of gnathos forming a disc||bryaula.|
|Apex of gnathos not forming a disc||5.|
|5.||Gnathos more or less sickle-shaped on lateral view.||6.|
|Gnathos not sickle-shaped on lateral view||8.|
|6.||Dorsal lobe of harpes flat, leaf-like||7.|
|Dorsal lobe of harpes not leaf-like; folded, and apex directed across harpe||omphalota.|
|7.||Costal margin of harpes almost straight||cenchrias.|
|Costal margin of harpes sinuate||caliginosa.|
|8.||Uncus deeply excised at base||calliploca.|
|Uncus not deeply excised at base||9.|
|9.||Dorsal lobe of harpes short, tusk-like||squamea.|
|Dorsal lobe of harpes not short||10.|
|10.||Uncus bent almost rectangularly||flavidella.|
|Uncus not bent rectangularly||11.|
|11.||Uncus rounded at apex||hamatella.|
|Uncus not rounded at apex||12.|
|12.||Uncus truncate at apex||hyetodes.|
|Uncus emarginate at apex.||habropis.|
List of figures.
Fig. 1.—Gymnobathra habropis Meyr. a, male genitalia, lateral view; b, harpe, inner view; c, juxta.
Fig. 2.—Gymnobathra hyetodes Meyr. a, male genitalia, lateral view; b, harpe, inner view; c, juxta, ventral view; d, juxta, lateral view; e, aedeagus; f, uncus, dorsal view.
Fig. 3.—Gymnobathra flavidella (Walk.). a, male genitalia, lateral view; b, harpe, inner view; c, juxta; d, tegumen, obliquely dorsal view; e, vinculum.
Fig. 4.—Gymnobathra hamatella (Walk.). a, male genitalia, lateral view; b, harpe, inner view; c, juxta; d, uncus, dorsal view; e, vinculum.
Fig. 5.—Gymnobathra coarctatella (Walk.). a, male genitalia, lateral view; b, harpe, inner view; c, juxta; d, aedeagus; e, uncus, dorsal view.
Fig. 6.—Gymnobathra squamea Philp. a, male genitalia, lateral view; b, harpe, inner view; c, juxta; d, aedeagus; e, vinculum.
Fig. 7.—Gymnobathra parca (Butl.). a, male genitalia, lateral view; b, harpe, inner view; c, juxta; d, aedeagus; e, uncus dorsal view; f, vinculum.
Fig. 8.—Gymnobathra calliploca Meyr. a, male genitalia, lateral view; b, harpe, inner view; c, juxta; d, aedeagus; e, tegumen, obliquely ventral view.
Fig. 9.—Gymnobathra cenchrias (Meyr.). a, male genitalia, lateral view; b, harpe, inner view; c, uncus, dorsal view; d, vinculum.
Fig. 10.—Gymnobathra bryaula Meyr. a, male genitalia, lateral view; b, harpe, inner view; c, juxta; d, aedeagus; e, uncus, ventral view.
Fig. 11.—Gymnobathra omphalota Meyr. a, male genitalia, lateral view; b, harpe, inner view; c, juxta; d, aedeagus; e, uncus, dorsal view; f, vinculum.
Fig. 12.—Gymnobathra caliginosa Philp. a, male genitalia, lateral view; b, harpes, inner view; c, uncus, dorsal view.
Fig. 13.—Gymnobathra tholodella Meyr. a, male genitalia, lateral view; b, harpes, inner view; c, juxta; d, aedeagus; e, uncus; f, vinculum.
Fig. 14.—Gymnobathra coarctatella (Walk.). Female genitalia, dorsal view; i.m., intersegmental membrane; s.r., segmental rods.
Fig. 15.—Gymnobathra flavidella (Walk.). Female genitalia, lateral view; s.r., segmental rods; c.o., copulatory opening.