♂, Mae Hong Son, Thailand. (RIEB)		♀, Nan, Thailand. (RIEB)
♂, Phrae, Thailand. (RIEB)	♂, Ranong, Thailand. (RIEB)	♂, Chiang Rai, Thailand. (RIEB)	♀, Chiang Mai, Thailand. (RIEB)

ON : Papilio cerberus Felder & Felder, 1865 OD : Reise Fregatte Novara, Lep. Rhop. (1):19-21. TL : "India septentrionalis: Bengalia, Assam". (NHML) Distribution : Sikkim, Assam, Bhutan, Bangladesh, Myanmar, Thailand, Laos, Cambodia, Vietnam, China, Langkawi, W.Malaysia, Singapore.

Papilio helena cerberus ♂f. eumagos Jordan, 1908 : in Seitz, Grossschmett. Erde 9:24. TL. Assam.
Papilio helena cerberus ♀f. azelia Jordan, 1908 : in Seitz, Grossschmett. Erde 9:24. TL. Assam.
Papilio helena cerberus ♀f. gypsothelia Jordan, 1908 : in Seitz, Grossschmett. Erde 9:24. TL. Tenasserim.
Ornithoptera helena euthycrates Fruhstorfer, 1913 : Deut. ent. Zeit. [Iris] 27(3):134. TL. Than-Moi, Tonkin.
Troides helena cerberus f. chongkiakwangi Tung, 1982 : Tokurana 4:7-8, 16,figs.1-C, B♀,C♀. TL. Malay Pen : Tapah Hills; Cameron HL; Ulu Groh. (IFS)

cerberus : ♂, Type, Silhet. (NHML, examined)
euthycrates : 1♂ 1♀, Syntypes (blue), Juni-Juli. Than-Moi, Tonkin. H.Fruhstorfer (NHML, examined)

[ THAILAND ]
Papilio helena cerberus ; Pendlebury,1923 : 22. (Nakhon Sri Thammarat: Khao Luang)
Papilio helena cerberus ; Godfrey,1930 : 206. (Nakhon Sri Thammarat: Khao Ram)
Papilio helena cerberus ; Godfrey,1932a : 263. (P)
Troides helena cerberus ; Pinratana,1977 : 3, figs.P2,♂,♀, 4, fig.P2,♀. (E / P)
Troides helena cerberus ; Ohya,1983 : 275, pl.114, figs.5,♂(Chiang Dao),7,♂(Chiang Dao). (Thailand)
Troides helena cerberus ; Haugum & Low,1985 : 249. (Thailand)
Troides helena cerberus ; Pinratana & Eliot,1992 : 11,39, pl.3, figs.2,♂,♀(f.eumagos), pl.4, figs.2,♂,♀(f.cerberus). (Chiang Mai; Nakhon Nayok; Tak; Chanthaburi; Ranong; Trang; Pattani; Satun)
Troides helena cerberus ; Matsuka,2001 : 187-188. (N: Chiang Dao; Chiang Mai; Doi Inthanon; Mae Mo / C: Thung Salaeng Luang; Phu Khieo; Doi Mussoe; Mae Sot; Thung Yai; Nakhon Nayok; Khao Khieo ; Khao Sa Bap / P: Ranong; Thung Na Kha; Khao Chong; Thale Ban; Pattani; Than To WF; Phuket I; Tarutao I.)
Troides helena cerberus ; Ek-Amnuay,[2007] : 62, pl.2, figs.P3,♂,♀,(f.cerberus), ♂,♀.(f.eumagos). (Chiang Mai; Wiang Pa Pao)
Troides helena cerberus ; Les Day,2011-2022 : Samui Butterflies, figs,♂,♂(Un),♀,♀(Un). (Koh Samui; Koh Phangan) (accessed: 2021.06.06)
Troides helena cerberus ; Kimura et al.,2011 : 111, figs.♂,♂(Un),f.cerberus; ♂,♂(Un),f.eumagos; ♀,♀(Un),f.cerberus; ♀,♀(Un),f.cerberus; ♀,♀(Un),f.eumagos. (Chiang Dao; Doi Inthanon; Khun Lao Village; Thung Saleng Luang; Phu Khiewo; Nakohn Nayok; Pliewn WF; Kaeng Chai; Mae Sohd; Doi Musso; Thung Yai; Khlong Naka; Ka Chong; Thaleban; Than To WF; Tarutao Is.)
Troides helena cerberus ; Ek-Amnuay,2012 : 62, pl.2, figs.P3,♂,♀,(f.cerberus), ♂,♀.(f.eumagos). (Chiang Mai; Wiang Pa Pao)
Troides helena cerberus ; S.Sophonviwatkul, C.Sunthornwiphat & T.Laola,2015- : Butterflies of Thailand, figs. (Chiang Mai; Phetchabun; Trat) (accessed: 2023.05.17)
Troides helena cerberus ; Küppers & Janikorn,2017 : 149-150, figs.Abb.Pa-042-047. (Phang Nga)

[ LAOS ]
Papilio helena f.♂. cerberus ; Dubois & Vitalis,1921 : 7. (Laos)
Papilio helena f.♀. aselia [sic] ; Dubois & Vitalis,1921 : 7. (Thado)
Papilio helena f.♀. gypsothelia ; Dubois & Vitalis,1921 : 7. (Laos)
Troides helena cerberus ; Motono & Negishi,1989 : 45, pl.1, figs.5,♂,6.♂(Un),7.♂,8.♂(Un). (Luang Prabang; Nam Moh; Ban Houei Sai; Vang Vieng; Phatong; Nam Ngum Dam)
Troides helena cerberus ; Osada, Uémura & Uehara,1999 : 200, pl.2, figs.♂,♀. (Luang Phrabang; Phong Saly)
Troides helena cerberus ; Matsuka,2001 : 188. (Phongsali; Muang Khoua; Nam Ngum Dam; Oudom Xay; Louang Namtha; Ban Houayxay; Louang Phrabang; Muang Xaignabouri; Muang Vangvieng; Lak Sao)
Troides helena cerberus ; Cotton & Racheli,[2007] : 321-322. (Thabok; Lak Sao; Hinboun: Phou Pha Man)
Troides helena cerberus ; Nakamura & Wakahara,2012 : 41.
Troides helena cerberus ; Suwa et al.,2013 : 6. (Thabok; Lak Xao; Oudom Xai; Phou Phoung; Bhamlong; Nahin; Vang Vieng)
Troides helena ; Suwa et al.,2019 : 5. (Chamlong; Nam Kat; Oudomsay)
Troides helena cerberus ; Onodera,2022 : 3, pl.3, figs.♂,♂(Un), pl.4, figs.♀,♀(Un). (Oudomxai; Luang Phabang: Marphouk)

[ CAMBODIA ]
Troides helena cerberus ; Ohya,1983 : 275. (Cambodia)
Troides helena cerberus ; Kosterin,2019 : 89, figs.2,♂,3,♂. (Koh Kong; Kep)
Troides helena cerberus ; Chartier & Kosterin,2022 : 113. (Kep; Koh Kong; Kampong Thom)

[ VIETNAM ]
Troides helena cerberus ; Fruhstorfer,1903 : 167. (Tonkin: Than Moi)
Papilio helena cerberus ♀f.gypsothelia ; Jordan,1909 : 24. (Tonkin)
Papilio helena f.♂. cerberus ; Dubois & Vitalis,1914 : 146. (Tonkin)
Papilio helena f.♂. cerberus ; Vitalis,1919 : 210. (Tonkin)
Papilio helena f.♂. cerberus ; Dubois & Vitalis,1921 : 7. (Tonkin)
Papilio helena f.♀. aselia [sic] ; Dubois & Vitalis,1921 : 7. (Tonkin)
Papilio helena f.♀. gypsothelia ; Dubois & Vitalis,1921 : 7. (Tonkin)
Papilio helena cerberus f.♂. cerberus ; Metaye,1957 : 80. (N)
Papilio helena cerberus f.♀. aselia [sic] ; Metaye,1957 : 80. (N)
Papilio helena cerberus f.♀. gypothelia ; Metaye,1957 : 80. (N)
Troides helena cerberus ; Ohya,1983 : 275. (Vietnam)
Troides helena euthycrates ; Haugum & Low,1985 : 251. (Tonkin: Than Moi)
Troides helena cerberus ; Ikeda et al.,1998 : 13, figs.3:3,♂,4,♀,9:2(♂genitalia). (Cuc Phuong)
Troides helena cerberus ; Shinkai,1999 : 47. (N:Tam Dao / S: Bao Lac)
Troides helena cerberus ; Matsuka,2001 : 188. (S)
Troides helena euthycrates ; Matsuka,2001 : 188. (N: Tam Dao; Than Moi; Cuc Phuong)
Troides helena ; Vu,2003 : 56. (Phu Quoc)
Troides helena euthycrates ; Luong et al.,2004 : 1, 17, figs.♂,♂(Un). (Cuc Phuong)
Troides helena cerberus ; Miyazaki, Saito & Saito,2006 : 7, figs.pa-2,♂,♀. (Lam Dong: Dambri)
Troides helena euthycrates ; Monastyrskii,2007 : 24-25, pl.1, figs.a♂,b♀. (N: Cho Moi; Than Moi; Hanoi; Na Hang; Ba Be; Tam Dao; Ba Vi; Cuc Phuong; Cat Ba; Bai Tu Long / C: Pu Huong; Ben En; Pu Mat; Vu Quang)
Troides helena cerberus ; Monastyrskii,2007 : 24-25, pl.1, figs.c♂,d♀. (C: Nui Chua; Bi Doup/Nui Ba; Da Teh / S: Dong Sai; Cat Tien)
Troides helena euthycrates ; Monastyrskii & Devyatkin,2015 : 11. (N)
Troides helena cerberus ; Monastyrskii & Devyatkin,2015 : 11. (C / S)
Troides helena cerberus ; Saito et al.,2017 : 77. (S: Nui Cam)

[ THAILAND ]
Mae Hong Son : 4♂ 1♀ (RIEB) (incl. photo).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Chiang Rai : 2♂ (RIEB) (incl. photo).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Chiang Mai : 10♂ 3♀ (RIEB) (incl. photo).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Lampang : 5♂ 2♀ (photo).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Phrae : 1♂ (RIEB).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Nan : 1♀ (RIEB).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Phetchabun : 4♂ (photo by T.Aoyama).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Trat : 4♂ 2♀ (photo by E.Ikari).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Ranong : 1♂ (RIEB).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Nakhon Si Thammarat : 2♂ (photo).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Satun (Koh Tarutao) : 2♂ (RIEB).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Yala : 1♂ 1♀ (photo & photo by S.Atdhabhan).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

[ LAOS ]
Khammouan : 4♂ 3♀ (photo by K.Saito).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

[ VIETNAM ]
Vinh Phuc : 3♂ 1♀ (photo by K.Saito).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Lam Dong : 1♂ (RIEB).

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

The butterfly is common in woodlands at low to high elevations (Alt. 30 - 2000m). Both sexes visit flowers. Males are frequently observed coming to the streams to suck water during the dry season in N.Thailand.
The taxon is highly variable in both sexes. Some authors treated euthycrates as a good subspecies. However, there are individual variations within the same locality that make it difficult to separate them clearly. Therefore I consider it is a synonym of ssp.cerberus.

Felder, C. & Felder, R.,1865-1875 :
Rhopalocera. In Reise der Osterreichischen Fregatte "Novara" um die Erde in den Jahren 1857, 1858, 1859 unter den Befehlen Commodore B. von Wullerstorf-Urbair. Zoologischer Theil. Zweiter Band:
Abtheilung. Wien : vi + 548 + [1] pp in 5 parts, 140 pls.

Jordan, K.,1908 : Die Indo-Australische Tagfalter. Papilionidae in Seitz, Grossschmett. Erde
9:17-24.

Fruhstorfer, H.,1913 : Neue Indo-Australiche Rhopaloceren.
Deut. ent. Zeit. [Iris] 27(3):130-139.

Tung, V.W.Y.,1982 : The population genetics of Troides species of Peninsular Malaysia and descriptions of two new female forms Papilionidae)
Tokurana 4:1-21.

Ohya, T.,1983 : Birdwing Butterflies
Kodansha, Tokyo. 331 pp, 136 pls.

Haugum, J. & Low, A.M.,1985 : A Monograph of the Birdwing Butterflies. Vol.2, part.3. Troides; helena & aeacus groups
E.J.Brill. Scandinavian Science Press LTD. Leiden, Copenhagen.

Matsuka, H.,2001 : Natural History of Birdwing Butterflies
Matsuka shuppan. 367 pp.

♂, Chiang Mai, Thailand.	♀, Mae Hong Son, Thailand.
♂, Nakhon Si Thammarat, Thailand.	♀, Chiang Mai, Thailand.
♂, Chiang Mai, Thailand.	♂, Chiang Mai, Thailand.
♀ and ♂, Chiang Mai, Thailand.

1996.09.26 - 2024.02.29.