Editing Papilio polyxenes (section)

==Morphology==
[[File:P1030326 copy filtered.jpg|thumb|Ventral view - female]]
[[File:Papilio polyxenesw.jpg|thumb|Caterpillar of ''Papilio polyxenes'' on ''[[Foeniculum vulgare]]'']]

===Eggs and larvae===
Eggs are pale yellow. Young larvae are mostly black and white with a saddle, and older larvae are green with black transverse bands containing yellow spots.<ref>{{cite journal | last1 = Timmerman | first1 = S | last2 = Berenbaum | first2 = MR | year = 1999 | title = Uric acid deposition in larva integument of black swallowtails and speculation on its possible functions | journal =Journal of the Lepidopterists' Society | volume = 53 | pages = 104–107 }}</ref>

===Caterpillar and chrysalis===
This caterpillar absorbs toxins from the host plants, and therefore tastes poor to bird predators.<ref name=":0" /> The black swallowtail caterpillar has an orange "forked gland", called the [[osmeterium]]. When in danger, the osmeterium, which looks like a [[snake]]'s tongue, everts and releases a foul smell to repel predators.<ref name=":0" />
[[File:Black Swallowtail Chrysalis by sdetwiler at wikimedia commons.jpg|thumb|Black swallowtail chrysalis, brown color morph]]

The [[pupa]]e may be green or brown, but not depending on surroundings or the background on which they have pupated. The color of the [[Pupa#Chrysalis|chrysalis]] is determined by a local genetic balance that ensures the majority of pupae will blend in.<ref name=CBIF>[http://www.cbif.gc.ca/spp_pages/butterflies/species/BlackSwallowtail_e.php Black Swallowtail], Butterflies of Canada</ref> A section of the green pupae will turn a much darker green at the very end of the pupae stage. This color change occurs a few hours to a full day before hatching.<ref name=CBIF/> Unusually, this butterfly's chrysalis is girdled with a loop, with its feet attached to the silk pad, which helps the butterfly to unfold its very large wings when crawling out.<ref name=ipr>{{cite web|title=Horticulture Friday, live at Reiman Gardens|url=http://iowapublicradio.org/programs/talk-iowa|website=Iowa Public Radio, Talk of Iowa|publisher=IPR|accessdate=27 March 2015|date=27 March 2015}}</ref>

===Sexual dimorphism===
[[File:Spinus-black-swallowtail-2015-07-n049145-w.jpg|thumb|right|''Papilio polyxenes'' female, [[Stokes State Forest]], New Jersey, United States]]
The black swallowtail has a wingspan of 6.9–8.4&nbsp;cm, and females are typically larger than males.<ref name=":0" /> The upper wing surface is black with two rows of yellow spots – these spots are large and bright in males and smaller and lighter in females. Females have a prominent blue area between these two rows, while males have a much less prominent blue area. These differences give rise to effective [[Batesian mimicry]] of ''[[Battus philenor]]'' seen in females.<ref name=":0">{{cite journal | last1 = Lederhouse | first1 = Robert C. | last2 = Silvio | first2 = G. Codella Jr | year = 1989 | title = Intersexual Comparison of Mimetic Protection in the Black Swallowtail Butterfly, ''Papilio polyxenes'': Experiments with Captive Blue Jay Predators | doi = 10.2307/2409216 | pmid = 28568560 | journal = Evolution | volume = 43 | issue = 2| pages = 410–420 | jstor = 2409216 }}</ref>

Both sexes show a red spot with a black bullseye on the inner hind margin of the hindwings and an isolated yellow spot on the front edge of the wings. The [[ventral]] side of wings of males and females are essentially identical: forewings have two rows of pale yellow spots, and hindwings have rows of bright orange spots separated by areas of powdery blue. The ventral side also acts as an effective mimic for both males and females for protection against predators.<ref name=":0" />