Some Pierine butterflies new to Malaysia
J.C. Moulton, Director of the Raffles Museum in Singapore, published this taxonomic note in 1923 describing Pierine butterflies (family Pieridae) new to various parts of the Malay Peninsula and Borneo, with particular emphasis on island forms from Pulo Aor and Pulo Tioman off the East Coast. The paper records three new subspecies and documents the puzzling occurrence of two Palearctic species in the tropics, likely introduced by human agency.
Summary
Moulton’s paper arises from his re-arrangement of the Raffles Museum butterfly collection, during which he identified several specimens representing forms not previously recorded from their localities. The central taxonomic contribution is the description of three new subspecies—Appias paulina grisea, Udaiana cynis tiomana, and Gandaca harina aora—all based on material from Pulo Aor and Pulo Tioman, small islands off the East Coast of the Malay Peninsula. These island forms are distinguished from their mainland counterparts by specific differences in wing coloration and marking: A. p. grisea by conspicuous lead-grey dusting at the wing bases, U. c. tiomana by fuscous infuscation on the underside of the hind-wing, and G. h. aora by a markedly reduced black distal border on the fore-wing. Moulton draws on comparative material from the Selangor Museum, the British Museum, the Hill Museum at Witley, and the Oxford collection to establish the diagnostic differences.
A second thread of the paper concerns the biogeographical anomaly of Pieris canidia and Pieris rapae in the region. P. canidia, known from India through Burma to China and the Philippines, had previously been recorded no further south than Tonkin or Hainan; its appearance in Singapore in 1922–1923, with no records from Peninsular Siam or the Malay Peninsula, strongly suggests introduction by human agency—possibly via larvae transported on vegetable matter to a major port. Similarly, P. rapae, a species ranging from Europe to Afghanistan and Kashmir, was recorded from Kuala Lumpur in December 1917, an occurrence Moulton considers explicable only by human-mediated introduction.
The remaining records include Appias libythea zelmira from Singapore and Pulo Aor (extending its known range southward), Phrissura aegis caepia from Brunei (a single male, provisionally placed under the Palawan subspecies name), and Hebomoia glaucippe aturia from Pulo Aor, which shows a pale lemon tinge distinguishing it from the dead-white Peninsula form and possibly linking it to the yellower Philippine forms.
Key Findings
- Three new subspecies described: Appias paulina grisea, Udaiana cynis tiomana, and Gandaca harina aora, all from Pulo Aor and Pulo Tioman (pp. 233–236).
- Pieris canidia recorded from Singapore (5♂♂, 2♀♀, May 1922–February 1923); previously known no further south than Tonkin or Hainan, suggesting human introduction (pp. 233–234).
- Pieris rapae recorded from Kuala Lumpur, December 1917 (teste C. B. Holman-Hunt); a species whose natural range extends only from Europe to Afghanistan and Kashmir (p. 234).
- Pulo Aor specimens collected by V. Knight on 13 June 1912; Pulo Tioman series from June–July 1916 (pp. 233–236).
- Type specimens of A. p. grisea and G. h. aora deposited in the British Museum (pp. 235–236).
- Phrissura aegis recorded from Brunei for the first time (11 June 1921, single male collected by a Dayak collector) (p. 235).
Conclusion
Moulton’s paper establishes that the small islands of Pulo Aor and Pulo Tioman harbour distinct Pierine subspecies not found on the adjacent mainland, reinforcing the biogeographical significance of island isolation in the East Coast region. Equally, the paper highlights the vulnerability of tropical port cities like Singapore to the accidental introduction of non-native species through maritime trade, a phenomenon already well documented in the island’s fauna.
Context
- Moulton served as Director of the Raffles Museum, Singapore, and the paper reflects the colonial-era practice of museum-based taxonomic description, with type specimens deposited in metropolitan institutions (the British Museum) and comparative material drawn from the F.M.S. Museums in Selangor.
- The study draws on collections at the Raffles Museum, Selangor Museum, British Museum, Hill Museum (Witley), and Oxford, representing the standard network of colonial and metropolitan entomological repositories of the period.