© The Author, 2009. Journal compilation © Australian Museum, Sydney, 2009 
Records of the Australian Museum (2009) Vol. 61: 73-87. ISSN 0067-1975 
doi:10.3853/j.0067-1975.61.2009.1523 
Two New Species of Gnathothlibus Wallengren from Fiji 
and Samoa and a New Species of Theretra Htibner 
from New Guinea (Lepidoptera: Sphingidae) 
Robert B. Lachlan 
Research Associate, Australian Museum, 
6 College Street, Sydney NSW 2010, Australia 
hawkmoth @ bigpond.com 
Abstract. Two new species of hawk moths from Fiji and Samoa, respectively Gnathothlibus fijiensis 
n.sp., and G. samoaensis n.sp., are described and figured, and distinguished from G. vanuatuensis 
Lachlan & Moulds, G. saccoi Lachlan & Moulds and G. eras (Boisduval). A new species of Theretra, 
T. tabubilensis n.sp. from Papua New Guinea is described and figured. The new species is distinguished 
from the sympatric T. indistincta papuensis Joicey & Talbot and Theretra clotho celata (Butler), and the 
lectotype of T. i. papuensis is designated. 
Lachlan, Robert B., 2009. Two new species of Gnathothlibus Wallengren from Fiji and Samoa and a new species 
of Theretra Htibner from Papua New Guinea (Lepidoptera: Sphingidae). Records of the Australian Museum 61(1): 
73-87. 
Three species of Gnathothlibus Wallengren, 1858 have 
been described from the southwestern Pacific region. 
Gnathothlibus eras (Boisduval, 1832) is reported, as a 
subspecies of G. erotus (Cramer, 1777), to occur from the 
Australian Region to Tahiti (D’Abrera, 1987), G. saccoi 
Lachlan & Moulds, 2001 [= G. mailed Schmit, 2002 (Schmit, 
2003)] and G. vanuatuensis Lachlan & Moulds, 2003 are 
known only from Vanuatu (Lachlan & Moulds, 2001, 2003; 
Schmit, 2002). 
Two undescribed species of Gnathothlibus, both closely 
resembling G. eras, and both previously confused with it, 
have been collected. One was collected in Fiji on the main 
island of Viti Levu in April, 2008, the other was collected 
on the island of Upolu, Samoa, in November, 2008. They 
are described in the present work. 
In the early 1990’s the author also collected a large series 
of males and females of another sphingid genus Theretra 
Hiibner, [1819], from the Tabubil area of the Western 
Province, Papua New Guinea. This collection could readily 
be classified into two species Theretra indistincta (Butler, 
1877) and a closely related but undescribed species. The two 
taxa are consistently distinct, no evidence of morphological 
intergradation was found despite several years of sampling 
and examination of large numbers of specimens. Evidently, 
sympatry has not resulted in hybridization. 
Bibliographic information and notes on the generic 
diagnoses of Gnathothlibus and Theretra are given by 
D’Abrera (1987). 
Materials and methods 
All specimens sampled at the various localities were 
collected using mercury vapour lights run from sunset to just 
before sunrise. The specimens were then deep frozen before 
being set for examination. All measurements are given in 
millimetres. This study was based on extensive material in 
the author’s private collection, (RBLC), and material in the 
Australian Museum, Sydney, (AM). Some specimens have 
been deposited in the Natural History Museum, London, 
(BMNH). Wing venation is that used by D’Abrera (1987). 
Morphological terminology used in this paper is based on 
that used by Kitching & Cadiou (2000). 
