"The male is yellow with four black 'tiger stripes' on each forewing. Females may be either yellow or black, making them dimorphic.
The yellow morph is similar to the male, but with a conspicuous band of blue spots along the hindwing, while the dark morph is almost completely black." -- Wikipedia
"The black swallowtail [above] has a wingspan of 6.9–8.4 cm, and females are typically larger than males. 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." -- Wikipedia