Parnassius is a genus of northern circumpolar and montane (alpine and Himalayan) butterflies usually known as Apollos. They can vary in colour and form significantly based on their altitude. They also show an adaptation to high altitudes called altitudinal melanism. They show dark bodies and darkened colouration at the wingbase which helps them warm faster using the sun.
Although classified under the Swallowtail butterfly family, none of the Parnassius species possess tails.
The larvae feed on species of plants belonging to the Papaveraceae and Crassulaceae families, and like the other swallowtail butterfly larvae, possess an osmeterium. Unlike most butterflies that have exposed pupae, they pupate inside a loose silken cocoon.
Identification and ecology 
The Parnassius species of butterflies are often hard to identify and can sometimes only be identified by dissection of the genitalia. The phylogeny of the group is still under study using molecular techniques. The exact number of species within the genus is disputed and numbers range from 38 to 47.
The Parnassius butterflies also have a peculiar reproductive strategy in that the male has special accessory glands that produce a mating plug that seals the female genitalia after mating. This is believed to ensure the success of the male and to prevent other males from mating and avoids sperm competition.
Butterflies of this genus have been widely used models to study metapopulations, population genetics and gene flow. Their patchy distribution and restricted migration makes them vulnerable to the effects of genetic drift and considerable colour variations can exist in individuals from different regions.
|A proposed phylogeny of the Parnassius and related groups.|
Eight subgenera are recognized within the genus.
- Driopa Korshunov, 1988. Type species: Papilio mnemosyne Linnaeus, 1758.
- Sachaia Korshunov, 1988. Type species: Parnassius tenedius Eversmann, 1851.
- Parnassius Latreille, 1804; Nouv. Dict. Hist. nat. 24 (6): 185, 199, Type Species: Papilio apollo Linnaeus.
- Tadumia Moore, ; Lepidoptera Indica, 5 (53): 116, Type Species: Papilio acco Gray
- Kailasius Moore, ; Lepidoptera Indica, 5 (53): 118, Type Species: Parnassius charltonius Gray
- Koramius Moore, ; Lepidoptera Indica, 5 (53): 120, Type Species: Parnassius delphius Eversmann
- Lingamius Bryk, 1935; Das Tierreich 65: 538-540, Type Species: Parnassius hardwickii Gray
- Eukoramius Bryk, 1935; Das Tierreich 65: 630, 673-674, Type Species: Parnassius imperator Oberthür
Other names that are no longer valid include
- Parnassis Hübner, ; Verz. bekannter Schmett. (6): 90 (or missp. or emend.?), Type Species: Papilio apollo Linnaeus
- Therius Billberg, 1820; Enum. Ins. Mus. Billb.: 75, Type Species: Papilio apollo Linnaeus
- Doritis Fabricius, 1807; Magazin f. Insektenk. (Illiger) 6: 283, Type Species: Papilio apollo Linnaeus
Important collections 
- National Museum of Natural History Leiden, (Rijksmuseum van Natuurlijke Historie) Curt Eisner collection. Types listed in Eisner, C. Parnassiidae-Typen in der Sammlung J.C.Eisner. Leiden. E.J.Brill, 1966. 190 pp. Col.frontispiece & 84 plts.(Zool.Verh. RMNH, 81). Review of worldwide species of Parnassiidae, 719 taxa included.
- Natural History Museum Specimens largely determined by Curt Eisner Types listed in Ackery, P. R. (1973): A list of the type-specimens of Parnassius (Lepidoptera: Papilionidae) in the British Museum (Natural History). Bull. Br. Mus. nat. Hist. (Ent.) 29 (1) (9.XI.1973): 1—35, 1 pl.pdf
- Muséum national d'histoire naturelle, Paris.Types listed by Bernardi, G., and Viette, P. 1966. Les types et typoides de Parnassius (s.l.) se trouvant au Museum de Paris. Bull.Soc. ent. Fr. 71 95-103, 163-166. 9 229-233, 304-309.
- Katoh T, Chichvarkhin A, Yagi T,Omoto K. 2005 Phylogeny and evolution of butterflies of the genus Parnassius: inferences from mitochondrial 16S and ND1 sequences. Zoolog Sci.22(3):343-51 PDF
- Ackery PR (1975) A guide to the genera and species of Parnassiinae (Lepidoptera:Papilionidae). Bull. Br. Mus. nat. Hist. (Ent.) 31, 4 pdf
- Nazari, Vazrick. 2006. Parnassius Latreille, 1804. Version 07 July 2006 (under construction).  in The Tree of Life Web Project,  shows Cladogram
- Ehrlich, A. H. and P. R. Ehrlich. 1978. Reproductive strategies in the butterflies: I. Mating frequency, plugging, and egg number. J. Kansas Entomol. Soc. 51: 666-697.
- Dechaine,Eric G. , Andrew P. Martin. 2004. Historic Cycles Of Fragmentation And Expansion In Parnassius smintheus (Papilionidae) Inferred Using Mitochondrial DNA. Evolution, 58(1):113–127
- Keyghobadi, N., Roland, J. and Strobeck, C. 1999. Influence of landscape on the population genetic structure of the alpine butterfly Parnassius smintheus (Papilionidae). Molecular Ecology 8: 1481–1495.
- Nazari, V., Zakharov, E.V., and Sperling, F.A.H., 2007. Phylogeny, historical biogeography, and taxonomic ranking of Parnassiinae (Lepidoptera, Papilionidae) based on morphology and seven genes. Molecular phylogenetics and Evolution, 42: 131-156. pdf
|Wikispecies has information related to: Parnassius|
- Collins, N.M., Morris, M.G., IUCN ,1985 Threatened Swallowtail Butterflies of the World: the IUCN Red Data Book (1985) IUCN pdf
- Wikimedia Commons has a gallery of Parnassius (see also the category).
- Parnassius of the World
- Göran Waldeck Links Page
- Tree of Life
- Genus Parnassius at Lepidoptera.pro
- Type specimens at ETH
- Images with text in Japanese.
- GloBIS/Gart Checklist
- GloBIS Database Includes type images
- Checklist of Parnassius of China
- NSG Genetic (DNA) vouchers
- Weiss (J.-Cl.) The Parnassiinae of the World