Violet Tinted Vista of Scarce Swallowtail Butterflies: Butterfly Bushes, English Lavender, Lilacs

Iphiclides podalirius is commonly known in English as scarce swallowtail or sail swallowtail or pear-tree swallowtail.

The common name of scarce swallowtail derives from the scarcity of this swallowtail's appearance in the British Isles, where it apparently makes stray pilgrimages or inquisitive explorations yet does not establish new colonies.

Another common name, sail swallowtail, describes the butterfly's graceful flight pattern of rapid wing flutterings followed by extended gliding. Taking advantage of upward air currents as well as its own propulsion, Iphiclides podalirius sails majestically and effortlessly across the sky.

As they float across the sky, with their triangular forewings resting in a straight line from tip to tip, scarce swallowtails resemble large, zebra-striped kites with streamers flowing from behind, unattached and free in blissful escapes from earth's gravitational pull.

An alternative common name, pear-tree swallowtail, recognizes the proclivity of the caterpillar and butterfly stages of Iphiclides podalirius for cultivated and wild species of pear trees. In particular, caterpillars frequently may be found on the common pear tree (Pyrus communis). Less often, although not rare, are their appearances on wild apple, or crab-apple, trees (Pyrus malus). Scarce swallowtail butterflies also extract nectar from other species of pears, such as the ornamental Pyrus ussuriensis, commonly known as Chinese pear or Manchurian pear or Siberian pear, which produces heart-shaped leaves, masses of fragrant white flowers, and small, hard pears of decided unpalatability to humans.

This affinity for pear trees was acknowledged in the delicate drawing by English entomologist-illustrator John Curtis (September 3, 1791 - October 6, 1862) which opened the fifth volume of his masterpiece, British Entomology, Being Illustrations and Descriptions of the  Genera of Insects Found in Great Britain and Ireland.

Interestingly, scarce swallowtail caterpillars actually display the greatest preference for host plants in the Prunus genus, such as:

• almond (Prunus amygdalus),
• European, or common, plum (Prunus domestica var. domestica),
• St. Lucie, or rock, cherry (Prunus mahaleb),
• sour cherry (Prunus cerasus), and
• sweet cherry (Prunus avium).

In particular, scarce caterpillars are associated with blackthorns (Prunus spinosa), which inevitably are studded with eggs or crawling with larvae when their habitats overlap.

The original scientific name of Papilio podalirius was bestowed by the father of modern taxonomy, renowned and ennobled Swedish botanist-physician-zoologist Carl Linnaeus (May 23, 1707 - January 10, 1778), in 1758. Sir Linnaeus' description was based upon a specimen collected in Livorno, northwest Italy by esteemed English naturalist John Ray (November 29, 1627 - January 17, 1705).

The genus name, Papilio, is derived from the Latin word for butterfly, which also had determined the family name of Papilionidae.

Sir Linnaeus selected the species epithet, podalirius, to honor Podaleirios (Ποδαλείριος), a legendary healer in Greek mythology who was the son of Asclepios (Ασκληπιός), the god of medicine and healing.

In 1807, German entomologist-illustrator Jacob Hübner (June 20, 1761 - September 13, 1826) devised another genus under the subfamily Papilioninae and named it Iphiclides in honor of Iphicles (Ιφικλής), half brother of Heracles (Ηρακλής), the strongest and one of the greatest heroes of ancient Greece.

The genus Iphiclides now consists of two to three species. In addition to podalirius, a sister species, Iphiclides podalirinus, commonly known as Chinese scarce swallowtail, is found only in China and southeastern Tibet.

Identified in 1832 by French entomologist Philogène Auguste Joseph Duponchel (1774 - January 10, 1846) as a subspecies of the scarce swallowtail, Iphiclides podalirius ssp. feisthamelii restricts its homeland primarily to the Iberian Peninsula, the department of the Eastern Pyrenees (département des Pyrénées-Orientales) in southwestern France, and the North African countries of Algeria, Morocco, and Tunisia. Commonly known as Southern swallowtail, Spanish swallowtail, or Spanish scarce swallowtail, this butterfly is regarded by some entomologists and taxonomists as distinct enough from scarce swallowtails to be considered as a separate, and therefore third, species in the Iphiclides genus.

Scarce swallowtails are an Old World butterfly in the family Papilionidae. They are considered natives of the Palearctic ecozone, which encompasses Europe, Asia north of the Himalayan foothills, and the northern and central Arabian Peninsula. Nevertheless, their natural distribution actually straddles the Indomalaya ecozone of south-southeast Asia with their nativity in Afghanistan, India, Pakisktan, and possibly Cambodia.

While occasionally sighted as far north as the British Isles and Sweden, scarce swallowtails are generally considered to be accidental strays or inquisitive explorers, not conscientious migrants, in those localities. In Belgium scarce swallowtails rarely visit the Flemish Region (Dutch: Vlaams Gewest), in the north, and are considered as a local but endangered species in the south.

While still considered as common with an indeterminate status of endangerment or threat, scarce swallowtails are protected by law in the Czech Republic, Germany, Hungary, Luxembourg, Poland, Russia, and Slovakia. Considered as rare in all of Austria's nine provinces, scarce swallowtails are protected in seven of them. Since 1993 scarce swallowtails, known in French as le Flambé ("flaming, flamed"), have been protected by law in l'Île-de-France (“isle of France”), the wealthiest and most populated administrative region, which is located in the northwest and includes Paris.

Scarce swallowtails comfortably inhabit both lowlands and highlands. Drawn to gardens, meadows, orchards, steppes, and open woodlands, they especially favor blackthorn (Prunus spinosa), or sloe, thickets.

Evincing adaptability to a variety of elevations, scarce swallowtails are found at altitudes of 5,249 feet (1,600 meters) in the Alps. Their widespread distribution throughout Bulgaria also encompasses the highest mountain range, at 9,596 feet (2,925 meters), in Bulgaria as well as the Balkan Peninsula, Rila (Bulgarian: Рила), where they freely fly up to 5,577 feet (1,700 meters). Similarly, in Russia scarce swallowtails range from Moscow's plains in the northwest to the rugged peaks of the Altai Mountains in the southeast.

Eggs:

Females oviposit, or lay, each egg singly on a carefully considered leaf. The decision to land on a potential plant is determined by sensory cues, such as visual or chemical. After landing, the final decision is based upon stimulants or deterrents detected by chemoreceptors which are located in the antennae, ovipositor (appendaged organ for laying eggs), proboscis (slender sipping tube), and tarsi, or feet (terminal segments of each leg).

Considerable time actually may be devoted to finding proper host plants because the fate of the egg and its larva, or caterpillar, depend on appropriate food sources. Oligophagous (Greek: ὀλίγος, oligos, “few” + φαγεῖν, phagein, “to eat”) in their diets, caterpillars mainly restrict their grazing to certain woody plants in the Rosaceae family, especially blackthorns (Prunus spinosa) and pear trees (Pyrus communis). Thus, the nourishment requirements of the larvae, the second stage of the life cycle, are considered in the fourth stage by the female scarce swallowtail as she makes decisions about the first stage.

Generally eggs are deposited onto the sunny areas of host plants.

Round in shape, eggs have cream yellow or pale green coloration.

Depending upon temperature, eggs hatch within one to four weeks.

Caterpillars:

The first instars, or developmental stages, of the caterpillar primarily are occupied with spinning a silk cushion onto their birth leaf as a resting site. Considered to be highly territorial, Iphiclides podalirius caterpillars also spin thread trails which subsequent instars rely upon in their forages to guide them back to their birth leaves. Threads are imbued with a unique volatile marker which ensures recognition by each caterpillar and precludes confusion over resting sites.

Robustly stout in the thorax, caterpillars taper distinctly towards their tail end.

The first two instars are largely blackened. Green bodies, which are marked with a yellow line along the middle of their backs, appear with the third instar. Yellow stripes slant across the sides and are spotted with orange to red dots.

Sixteen feet extrude along the bottom of the body. Six emerge from the pectoral region while the abdomen has eight. There are two anal feet.

Pupation lasso:

In the third stage of its life cycle, the scarce swallowtail pupa affixes itself to a surface, such as a leaf or stem, at its tapered tail and lassoes itself around its thorax.

Blending with their surroundings, pupae in late spring are green while those in late autumn, which overwinter, are brown.

The number of generations produced within one year is determined by altitude and latitude. In central Europe and at higher altitudes, only one generation, flying from May to July, is evinced. In the Mediterranean region, scarce swallowtails are multivoltine as two or three generations usually are produced annually. The first flight of the metamorphosis from the overwintering pupae occurs as early as March. The second flight appears in July and August.

Emergence as a butterfly signifies the fourth, or flight, stage in the scarce swallowtail's life cycle.

In addition to tree flowers, scarce swallowtails are attracted to other flowering plants. Especially tints of floral violet entice and satisfy them. Four violet-tinted flowers which particularly guarantee endless nectarivorous fascination from scarce swallowtails are

• butterfly bushes (Buddleia davidii),
• English lavender (Lavandula angustifolia), and
• lilacs (Syringa vulgaris).

Buddleia davidii, or Buddleja davidii, is commonly known as butterfly bush or summer lilac.

An Old World plant, butterfly bushes have a native distribution from central China to Tibet. As one of the cold hardiest Buddleia, butterfly bush flourishes at high altitudes up to 7,800 feet (2,600 meters). The U.S. Department of Agriculture Plant Hardiness Zones Map, which classes plants according to the coldest temperature at which they remain viable, identifies butterfly bush as thriving from Zone 4 to Zone 9 (-30 to 30 °F; -34 to -1 °C).

Long popular as an ornamental since its introduction onto the world garden stage at the end of the nineteenth century, butterfly bush adapts easily to temperate areas as well as to such adversities as drought, intense heat, high humidity, and poor soil.

With so many spectacular cultivars continuously being bred from Buddleia davidii, it is universally familiar and is considered to be integral to attractive, fragrant gardens.

Particularly receptive to full sunlight, butterfly bush reaches a height of 10 to 17 feet (3 to 5 meters) and has a spread of 17 feet (5 meters).

Long, lance-shaped leaves, which are paired oppositely along branches, have medium green to grey green to dark green uppersides and woolly white undersides.

Opening profusely and fragrantly by mid-summer, butterfly bush flowers last until the first frost. Small, tubular florets, or tiny flowers, form cone-shaped clusters known as panicles (Latin: panicula, "tuft on plants"). With four spreading petals apiece, each floret petitely measures about 0.5 inches (1 centimeter) in length and 0.1 inches (3 millimeters) in width.

Floral colors range from white to golden yellow and from pink to light blue to lavender and from mauve to red purple. Violet or purple tints such as lavender and mauve especially cast a phenomenally irresistible spell upon scarce swallowtails, which, nevertheless, are completely devoted to any incarnation of butterfly bush.

Exuberantly responding to full sun, English lavender reaches a height of 2 to 3 feet (0.6 to 0.9 meters) and spreads to a generous width of 4 feet (1.2 meters).

Narrow, grey leaves are softened with down.

Flowers open fragrantly in lavender spikes in early summer.

Syringa vulgaris is known in English as lilac or common lilac or French lilac.

Of the almost two dozen species of Syringa, only two are native to Europe: Syringa josikaea, known as Hungarian lilac, and Syringa vulgaris. All the others are primarily native to northeast Asia. Syringa vulgaris has graced gardens in western Europe since the sixteenth century.

This Old World favorite was transported in the early days of the American colonies as a vital component of herb gardens, which were grown for culinary, medicinal, and ornamental purposes.

The enduring appeal of Syringa vulgaris is evinced in the development of over 1,500 cultivars from this amiable shrub.

According to the U.S.D.A. Plant Hardiness Zones Map, lilacs remain viable in Zones 4 through 9 (-30 to 30 °F; -34 to -1 °C).

Appreciating full sun, lilacs have an equiproportional shape with a height and a spread of 20 feet (6 meters).

Dark green leaves are paired on opposite sides of stout stems or branches. Cordate (Latin: cor, "heart") leaves point the tip of their heart shape outward while the doubly curving top arches away from the petiole (Latin: petiolus, "little foot"), that is, the stalk which attaches the leaf blade to the stem.

In late spring to early summer showy flowers open fragrantly and profusely in cone-shaped panicles of blue, white, lavender, or deep purple.

As scarce swallowtails flutter, glide, and swoop through gardens and countrysides, they target three preferential nectar sources which embellish the Old World's iconic architectural and pastoral landscapes with a spectrum of violet tints. All three nectar sources have garnered worldwide acclaim among humans for their unfailingly pleasant fragrances and impressive visual appeal. As such, scarce swallowtails do not have to conduct vain, extensive searches for these nectarous treasures. Moreover, they generously share these violet-tinted settings with other winged admirers. As a result, any and all observers who happen upon the scene are rewarded with a serene vista of stunning natural beauty, fragranced with familiar, enticing aromas and graced with the elegant flow of faunal and floral harmony.

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Scarce swallowtail (Iphiclides podalirius): Jean-Raphaël Guillaumin (JR Guillaumin), CC BY-SA 2.0, via Flickr @ https://www.flickr.com/photos/jrguillaumin/2689023481/

specimen captured via William Henry Rudston Read's (b.5/14/1808) hat, 1822, Slough nursery garden, south central England: John Curtis (1823-1840), British Entomology Vol. V, Plate 578, Not in copyright, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/8221568

oil on canvas portrait of John Ray painted by unknown artist after 1680 ~ National Portrait Gallery, London: Public Domain, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:John_Ray_from_NPG.jpg

Musée du Louvre: Department of Greek, Etruscan and Roman Antiquities, Sully, first floor, room 43, case 23: Marie-Lan Nguyen (Jastrow), Public Domain, via Wikimedia Commons @ https://it.wikipedia.org/wiki/File:Herakles_strangling_snakes_Louvre_G192.jpg

J. Hübner, Das kleine Schmetterlingsbuch (1934), page 17; illustration from J. Hübner, Sammlung europäischer Schmetterlinge (1805): Internet Archive Book Images, No known copyright restrictions, via Flickr @ https://www.flickr.com/photos/internetarchivebookimages/20845927401/

Huesca, Aragón, northeastern Spain: www.invertebradosdehuesca.com, CC BY 3.0 ES, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Iphiclides_feisthamelii_male.jpg

Sleedoorn bloemen (Prunus spinosa) Blackthorn: Rasbak, CC BY-SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Sleedoorn_bloemen_(Prunus_spinosa).jpg

chrysalis by Vincent-Louis Jourdin-Pellieux (1805-1883); caterpillar landscape by P. Duménil; P.-A.-J. Duponchel, Iconoraphie (1849), Vol. 1, Plate I, opp. p. 40: Public Domain, via Internet Archive @ https://archive.org/details/iconographieethi01dupo/page/n46/mode/1up?view=theater; via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/10139027

northeastern Italy: Fabio Stergulc, Università di Udi, Bugwood.org, CC BY 3.0, via Forestry Images @ https://www.forestryimages.org/browse/detail.cfm?imgnum=1297019

osmeterium not visible: Andre Abrahami (Abrahami), CC BY-SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Flambé-chenille.JPG

osmeterium visible: Andre Abrahami (Abrahami), CC BY-SA 3.0, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Flambé-chenille2.JPG

Scarce Swallowtail (Iphiclides podalirius) pupa: Dean Morley (Deanster1983), CC BY-ND 2.0, via Flickr @ https://www.flickr.com/photos/33465428@N02/6870100821/

hindwing closeup: Dean Morley (Deanster 1983), CC BY-ND 2.0, via Flickr @ https://www.flickr.com/photos/33465428@N02/4555072311/

butterfly bush (Buddleja): Jean-Raphael Guillaumin (JR Guillaumin), CC BY-SA 2.0, via Flickr @ https://www.flickr.com/photos/jrguillaumin/3752382168/

Veneto, northeastern Italy: Silvano Albero, CC BY-SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Iphiclides_Podalirius.JPG

lavender (Lavandula): Mickaël Mottin, Licence Art Libre 1.3 (LAL 1.3)(Free Art License 1.3), via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Iphiclides_podalirius01.jpg

Karlsruhe, southwestern German: H. Zell, CC BY-SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Lavandula_angustifolia_003.JPG

Les Baux-de-Provence, southeastern France: Grez, CC BY-SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Iphiclides_podalirius_on_lilac.jpg

Iphiclides podalirius with its favorite color: György Nádudvari (Reedcourty), CC BY-SA 2.5, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Kardos_lepke_Iphiclides_podalirius_001.jpg

dorsal (upperside) view of scarce swallowtail: Ymaup, CC BY-SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Flambe3.jpg

illustration by Scottish naturalist James Duncan (1804–1861); J. Duncan, British Butterflies (1855), Plate IV, opp. p. 94: Not in copyright, via Internet Archive @ https://archive.org/details/britishbutterfli00dunc/page/n100/mode/1up?view=theater; Public Domain, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/15851092

Kolymbia, northeastern Rhodes: Böhringer Friedrich, CC BY-SA 2.5, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Segelfalter04.JPG

Abadjiev, Stanislav. An Atlas of the Distribution of the Butterflies in Bulgaria: Lepidoptera Hesperioidea & Papilionoidea. Zoocartographia Balcanica Volume 1. Sofia Bulgaria: Pensoft Publishers, 2001.

Carey, Dennis, and Tony Avent. “Buddleia --- The Butterfly Bush.” Plant Delights Nursery > Plant Articles. January 8, 2010. Plant Delights Nursery, Inc. Web. www.plantdelights.com

• Available at:  http://www.plantdelights.com/Buddleia-Butterfly-Bushes-for-the-Garden/products/497/

Cheshire, Steven. “Scarce Swallowtail Iphiclides podalirius (Linnaeus, 1758).” British Butterflies : Species : Species Account. Steve Cheshire. Web. www.britishbutterflies.co.uk

• Available at:  http://www.britishbutterflies.co.uk/speciesinfo.asp?vernacular=Scarce+Swallowtail 

Collins, N. Mark and Michael G. Morris. Threatened Swallowtail Butterflies of the World: The IUCN Red Data Book. Gland, Switzerland: International Union for Conservation of Nature and Natural Resources, 1985.

Curtis, John. British Entomology, Being Illustrations and Descriptions of the Genera of Insects Found in Great Britain and Ireland: Containing Coloured Figures from Nature of the Most Rare and Beautiful Species, and in Many Instances of the Plants Upon Which They Are Found. Volume V: Lepidoptera, Part I. London: Richard Taylor, 1823-1840.

• Available via Biodiversity Heritage Library at: http://www.biodiversitylibrary.org/item/34105

Donovan, Edward. The Natural History of British Insects; Explaining Them in Their Several States, with the Periods of Their Transformations, Their Food, Oeconomy, &c. Together with the History of Such Minute Insects as Require Investigation by the Microscope. The Whole Illustrated by Coloured Figures, Designed and Executed from Living Specimens. Vol. IV. London: F. and C. Rivington, MDCCXCV (1795).

• Available via Internet Archive at: http://archive.org/details/naturalhistoryof495dono

Duncan, James. "Scarce Swallow-Tail Butterfly. Papilio Podalirius." Pages 96-99. British Butterflies. The Naturalist's Library, Vol. XXIX. Edinburgh: W.H. Lizars; London: Henry G. Bohn, 1855.

• Available via Biodiversity Heritage Library at: https://www.biodiversitylibrary.org/page/15851096
• Available via Internet Archive at: https://archive.org/details/britishbutterfli00dunc/page/97/mode/1up?view=theater

Duponchel, Philogène Auguste Joseph. "1. Papillon Flambé." Iconographie et Histoire Naturelle des Chenilles pour Servir de Complément à l'Histoire Naturelle des Lépidoptères ou Papillons de France de MM. Godart et Duponchel. Tome premier (Diurnes): 40. Paris: Germer Baillière, Libraire-Éditeur, 1849.

• Available via Biodiversity Heritage Library at: https://www.biodiversitylibrary.org/page/10139026
• Available via Internet Archive at:  https://archive.org/details/iconographieethi01dupo/page/40/mode/1up?view=theater

Flora: A Gardener’s Encyclopedia. Volumes I-II. Portland OR: Timber Press, 2004.

Hübner, Jacob. "835. I. podalirius Linn. Sys. Pap. 36. Hübn. Pap. 388, 389." Verzeichniss bekannter Schmettlinge: 82. Augsburg: bey dem Verfasser zu Finden, 1816-1819.

• Available via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/33045121
• Available via Internet Archive @ https://archive.org/details/verzeichnissbeka00hb/page/82/mode/1up?view=theater

Hübner, Jacob. "Lepidoptera, I. Papiliones, II. Gens, B. 388, 389 Podalyrius." Sammlung europäischer Schmetterlinge errichtet von Jacob Hübner in Augsburg. Plates, vol. 1: 77. [Augsburg: n.p.], 1805.

• Available via Biodiversity Heritage Library at: https://www.biodiversitylibrary.org/page/28057928

Hübner, Jacob; Friedrich Schnack. "Segelfalter (1, 2). Schwalbenschwanz (3, 4)." Das kleine Schmetterlingsbuch: kolorierte Stiche von Jacob Hübner. Geleitwort von Friedrich Schnack. Insel-Bücherei Nr. 213: page 17 (figures 1, 2). Leipzig: Insel-Verlag, [1934].

• Available via Biodiversity Heritage Library at: https://www.biodiversitylibrary.org/page/43194360
• Available via Internet Archive at: https://archive.org/details/daskleineschmett01hubn/page/n6/mode/1up

La Croix, Isobyl. The New Encyclopedia of Orchids: 1500 Species in Cultivation. Portland OR: Timber Press, 2008.

Lafranchis, Tristan. Les Papillons de jour de France, Belgique et Luxembourg et leurs chenilles. Mèze, France: Collection Parthénope, éditions Biotope, 2000.

Merian, Maria Sibylla. De Europische Insecten. Amsterdam: J.F. Bernard, 1730.

Le ministre de l'agriculture et de la pêche et le ministre de l'environnement. “Arrêté du 22 juillet 1993 relatif à la liste des insectes protégés en région Ile-de-France complétant la liste nationale.” LegiFrance Accueil> Les autres textes législatifs et réglementaires. Dernière modification : 19 avril 2007; Version en vigueur au 14 novembre 2013. Secrétariat général du Gouvernement. Web. www.legifrance.gouv.fr

• Available at:  http://www.legifrance.gouv.fr/affichTexte.do?cidTexte=JORFTEXT000000728852&dateTexte=&categorieLien=id

Linnaei, Caroli. "Podalirius." Systema Naturae per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, Cum Characteribus, Differentiis, Synonymis, Locis. Tomus I: 463. Holmiae: Laurentii Salvii, 1758.

• Available via Biodiversity Heritage Library at: https://www.biodiversitylibrary.org/page/727374

Moerman, Daniel E. Native American Medicinal Plants: An Ethnobotanical Dictionary. Portland and London: Timber Press, 2009.

Muséum national d'Histoire naturelle [Ed]. 2003-2010. “Iphiclides podalirius (Linnaeus, 1758) Flambé (Français).” Inventaire national du Patrimoine naturel: Recherche de données Rechercher une espèce Fiche espèce. Muséum national d'Histoire naturelle. Web. inpn.mnhn.fr

• Available at:  http://inpn.mnhn.fr/isb/espece/cd_nom/54475

Nash, Ned, and Isobyl la Croix, eds. Flora's Orchids. Portland OR: Timber Press, 2005.

Nemos, F. Europas bekannteste Schmetterlinge. Beschreibung der wichtigsten Arten und Anleitung zur Kenntnis und zum Sammeln der Schmetterlinge und Raupen. Berlin: Oestergaard Verlag, ca. 1890s.

Quattrocchi, Umberto. CRC World Dictionary of Plant Names: Common Names, Scientific Names, Eponyms, Synoyms, and Etymology. Four volumes. Boca Raton-London-New York-Washington DC: CRC Press, 1999.

Raven, Charles Earle. John Ray, Naturalist: His Life and Works. Cambridge Science Classics series. Cambridge: University of Cambridge Press, 1986.

Salmon, Michael A. The Aurelian Legacy: British Butterflies and Their Collectors. With additional material by Peter Marren and Basil Harley. Berkeley and Los Angeles: University of California Press, 2000.

Stefanescu, Constantí, Jordi Jubany, and Jordi Dantart. “Egg-laying by the butterfly Iphiclides podalirius (Lepidoptera, Papilionidae) on alien plants: a broadening of host range or oviposition mistakes?” Animal Biodiversity and Conservation, Volume 29, Issue 1 (2006): 83-90.

Available at:  http://w3.bcn.es/fitxers/icub/museuciencies/abc291pp8390.763.pdf 

Tolman, Tom, and Richard Lewington. Butterflies of Britain and Europe. London: Harper Collins, 1997.

Watson, Les, and Michael John Dallwitz. “Iphiclides.” DELTA – DEscription Language for TAxonomy > British Insects: Butterflies. Version: 29th December 2011. Institute of Botany: Chinese Academy of Sciences. Web. delta-intkey.com

• Available at:  http://delta-intkey.com/britin/pap/www/iphiclid.htm 

Westwood, John Obadiah. British Butterflies and Their Transformations. Illustrations by H.N. Humphreys. London: William Smith, 1841.

Wiemers, Martin, and Brigitte Gottsberger. “Discordant patterns of mitochondrial and nuclear differentiation in the Scarce Swallowtail Iphiclides podalirius feisthamelii (Duponchel, 1832 (Lepidoptera: Papilionidae).” Entomologische Zeitschrift Stuttgart, Vol. 120, No. 3 (June 2010): 111-115.

Wilkinson, R.S. "The Scarce Swallow-tail: Iphiclides podalirius (L.) in Britain." The Entomologist's Record and Journal of Variation, Vol. 87, Nos. 11 and 12 (November/December, 1975): 289-293.

• Available at:  http://archive.org/details/entomologistsrec871975tutt

Xerces Society and Smithsonian Institution. Butterfly Gardening: Creating Summer Magic in Your Garden. San Francisco: Sierra Club Books, 1998.