Article

Dragonflies

From Munshipedia, the MBRAS digital historical encyclopedia

Dragonflies

Dragonflies of the Malay Peninsula and Borneo have been the subject of sustained taxonomic investigation since the early twentieth century, with the genus Macromia—a group of large, strong-flying insects—serving as a focal point for systematic revision across the Indo-Malayan region. At least eighteen species of Macromia were recognised from the Orient by 1922, a number Laidlaw anticipated would increase considerably [1, p. 219]. The broader odonate fauna of the Malaysian area, encompassing both dragonflies (Anisoptera) and damselflies (Zygoptera), was documented through museum-based surveys and field expeditions that revealed a rich and poorly known assemblage, with collections from interior highlands and isolated island groups yielding a notable proportion of new and rare species [2, p. 56], [3, p. 219].

Taxonomic Framework and Genus Macromia

The systematic treatment of Macromia by F. F. Laidlaw in 1922 established a morphological framework for distinguishing among the genus’s species based on the shape of the anal appendages and genital structures of the male’s second abdominal segment, the size of the pterostigma, the presence or absence of metallic lustre on abdominal segments 2–6, and the form of the dorsal process on the tenth segment [1, p. 219]. Laidlaw organised the species into three principal groups: the M. westwoodi group, characterised by a metallic-lustre abdomen and small pterostigma; the M. cincta group, with a non-metallic abdomen, larger pterostigma, and a distribution confined to Malaya and Indo-China; and the M. calliope group, defined by Ris, with a black thorax bearing a humeral band and no dorsal process on segment 10 [1, p. 219].

The paper’s principal contribution was the description of three new species: M. cydippe from Borneo (male hind-wing 40 mm), M. corycia from Borneo (male hind-wing 34 mm), and M. callisto from the Malay Peninsula (male hind-wing 31.5 mm, the smallest Oriental species of the genus) [1, pp. 219–226]. Laidlaw also re-examined M. westwoodi, arguing that the male previously attributed to it by de Selys and Kruger actually belongs to a different species, and identified a curious structural thickening on the ventral margin of the tenth tergite in the cincta group that may be functionally connected to the genitalia [1, pp. 224–225]. The material derived largely from the Raffles Museum, Singapore, and the British Museum, supplemented by specimens from Tonkin, the Khasi Hills, and India [1].

The difficulty of capturing these insects was noted explicitly: Kennedy (1915) was compelled to use a shotgun to obtain his first specimens of the American M. magnifica, and Laidlaw himself observed that the genus “will repay careful study in the field” [1, p. 219]. Bornean species were listed as M. cincta (forma), M. cydippe, M. corycia, and M. euterpe, with M. borneensis, M. westwoodi, and M. gerstaeckeri included with some doubt; the Malay Peninsula yielded only M. westwoodi and M. callisto [1, p. 228].

A separate but related taxonomic contribution concerned the genus Macromidia (Corduliinae, Macromiina), a purely Oriental group of three species distinguished from Macromia by more rounded wings, cross-veins beyond the nodus, a relatively long pterostigma, and a tibial keel on all three leg pairs in the male [4, p. 230]. Laidlaw described Macromidia genialis from Gunong Tahan in Pahang, a single male collected by F. N. Chasen on 3 December 1921 at 1000 ft elevation, with a hind-wing of 27.5 mm and an abdomen of 28.5 mm plus 1.5 mm for anal appendages [4, p. 231]. The species was distinguished from its congeners M. rapida and M. fulva by its smaller size and by a single row of cells (about seven) following the forewing triangle to near the nodus, where the other two species have two rows [4, p. 231]. The species was named in association with the mountain’s presiding Jin, in the hope that the deity may guard its forest treasures [4, p. 230].

Faunal Surveys and Island Biogeography

The 1924 survey of the dragonfly fauna of the Malay Peninsula, published in two parts, provided a foundational reference for the region’s odonate biodiversity, treating the damselfly sub-families Epallaginae, Amphipteryginae, Megapodagrioninae, and Platystictinae with diagnostic characters, species descriptions, and a distributional table [5]. Laidlaw proposed the term Malayan to denote a species pertaining to the Malay Peninsula and Malaysian pertaining to the area especially inhabited by the Malaysian fauna, namely Borneo, Sumatra, Java, and the Peninsula, with the odonate area also including the Philippine Islands and possibly Celebes [5, p. 307].

Among the Epallaginae, the genus Pseudophaea was treated in detail, with species falling into several groups. The ochracea group, regarded as the least differentiated and possibly most primitive, included P. ochracea (hind-wing 27.5 mm, ranging from Malacca north to Patani) and P. brunnea (hind-wing about 30 mm, from Burma and possibly Tonkin) [5, p. 297]. The variegata group, confined to the Peninsula, Borneo, Sumatra, and Java, was richest in Borneo with four species; Laidlaw noted that the males were “amongst the most brilliant of oriental insects, and they are exceeded by none in elegance of form” [5, p. 298]. The genus Dysphaea was distinguished from Pseudophaea by long narrow wings with an abruptly defined pattern of rich brownish black; D. lugens measured 32–34 mm in hind-wing length and 41 mm in abdomen, while D. dimidiata was smaller at 30 mm hind-wing and 36 mm abdomen [5, p. 300].

In the Megapodagrioninae, the genus Rhinagrion was described as highly specialised and occupying an isolated position, with colouring of bright green, orange-brown, yellow, and black combining to give a startling effect [5, p. 302]. The genus Podolestes was confined to the Peninsula, Sumatra, and Borneo, with two species distinguished by the number of post-nodal cross-nerves: P. orientalis had 19 or more (Kruger recorded up to 23), while P. chrysopus had only 15–18 [5, p. 302].

The Platystictinae, found about small, shady forest-streams where their tenuity and colouring afforded sufficient concealment, were noted as being generally rare in collections, with specific differences often discoverable only in the structure of the male anal appendages [5, p. 303]. Drepanosticta sharpi from Jor, Perak, had an abdomen of 45 mm and hind-wing of 25 mm, while an unnamed species from the same locality had an abdomen of 30 mm and hind-wing of 18.5 mm [5, pp. 304–305]. Protosticta forsteri, known from a single female type collected by Laidlaw at Kuala Aring, Kelantan, and a male from Jor, Perak, had a hind-wing of approximately 17.5 mm against an abdomen of 38 mm in the male [5, p. 306].

The 1926 paper on the Mentawi Islands extended this faunistic work to a deep-water island group lying 60–80 miles west of Sumatra, separated from it by the deep Mentawi Basin (500–1000 fathoms) [3]. Laidlaw recorded 34 species of Odonata from the 1924 collection, nearly matching the 35 species Ris had listed from Simalur Island in 1915, and estimated the list represented less than 80 per cent of the total fauna [3, p. 219]. The central argument was that deep-water isolation had produced a distinct island fauna, characterised by the absence of certain widespread Oriental genera, the presence of endemic subspecies, and the inclusion of a few species of decidedly eastern or Papuan range [3]. The genera Trithemis, Rhinocypha, and Coeliccia were entirely absent from two fairly large collections, a pattern Laidlaw interpreted as evidence that these were late arrivals in the Malaysian region [3, p. 219]. One new species, Drepanosticta krugeri (Platystictidae), was described with a male abdomen of 39 + 0.75 mm and hind-wing of 24 mm, characterised by a paired club-shaped prothoracic process and a pentagonal pterostigma [3, pp. 228–229]. Two new subspecies were also named: Caconeura verticalis karnyi and Amphicnemis louisae smedleyi [3, pp. 230–232].

Field Expeditions and Collection Methodology

The 1911 Moulton-led expedition to Mount Batu Lawi in the upper Limbang–Madihit region of Sarawak provided a significant contribution to the known odonate fauna of the Borneo highlands [2]. The party, which included J. C. Moulton, H. N. Ridley, and several other collectors, travelled up the Limbang River to the Kuala Madihit and then overland through previously unexplored mountainous country to reach Batu Lawi, whose summit rises to approximately 6,400 ft above sea level [2, pp. 39–40]. The region was extremely sparsely populated and had seen only a handful of European visitors in the preceding half-century [2]. Despite the hurried and difficult nature of the journey—31 of the 40 days were spent in actual travelling, with long stretches devoid of any native settlement—the collections proved “surprisingly rich in new and rare species,” indicating the poorly known nature of the fauna in this interior highland zone [2, p. 56]. The area between the Madihit headwaters and Batu Lawi contained no native inhabitants, and the party spent 13 days without encountering anyone outside their own party [2, p. 56]. Neurobasis chinensis, a rich green dragonfly, was recorded during the river journey and noted as occurring in Sarawak only in upper reaches of rivers [2, p. 10].

The 1924 Mentawi expedition, which included N. Smedley (Raffles Museum, Singapore) and H. H. Karny (Zoological Museum, Buitenzorg), collected from sea-shore, lowland, swamp, cultivated areas, and accessible hills near the Government stations of Siberut and Sioban [3]. The primary material from both expeditions was held at the Raffles Museum, Singapore, and the Zoological Museum, Buitenzorg, with specimens distributed among collectors C. B. Kloss, N. Smedley, and H. H. Karny [3].

Research and Documentation

The Society’s literature on dragonflies and damselflies reflects a cumulative, museum-driven programme of taxonomic revision that intensified from the 1910s through the 1920s. Laidlaw’s work, spanning the Straits Branch and Malayan Branch periods, represents the dominant thread: from the 1912 Batu Lawi expedition report [2], through the 1922 Macromia revision [1], the 1923 Macromidia genialis note [4], the 1924 two-part faunal survey [5], and the 1926 Mentawi paper [3], each publication built directly on the preceding one, extending generic and species-group concepts across the Straits Settlements, Borneo, Sumatra, and the deep-water islands of the West Sumatran chain. The methodology was characteristically collection-based, drawing on the Raffles Museum, Singapore, and the British Museum (Natural History), with field material supplied by collectors operating under the administrative infrastructure of British Malaya, including Waterstradt, Chasen, and Annandale [5]. The shift from single-species descriptions to comprehensive regional surveys, and from mainland to island biogeography, marks the evolution of odonate research within the Society’s pages from a descriptive enterprise to one increasingly concerned with faunistic patterns and the significance of deep-water isolation in shaping regional biodiversity [3, p. 219].

MBRAS Sources

References

  1. F.F. Laidlaw (1922). Some notes on oriental dragonflies: the genus Macromia JSBRAS 85: 218–229. Read on JSTOR
  2. F.F. Laidlaw (1912). List of the Odonata taken on an expedition to Mt. Batu Lawi together with descriptions of supposed new species JSBRAS 63: 92–99.
  3. F.F. Laidlaw (1926). Spolia mentawensia: dragonflies (Odonata JMBRAS 4(2): 214–233. Read on JSTOR
  4. F.F. Laidlaw (1923). On a new and interesting dragonfly (Odonata) from Gunong Tahan JMBRAS 1(1): 231–232.
  5. F.F. Laidlaw (1924). A survey of the dragonfly fauna of the Malay Peninsula, with notes on that of neighbouring countries. Part II JMBRAS 2(3): 296–308. Read on JSTOR