Wow! What a resource! They have all kinds of good info about butterflies, including, by species, habitat, host plants, descriptions, sighting frequency and occurrence, and more.
Check out their “Species List!“
On their “Spicebush Swallowtail Pterourus troilus” page, they say:
Butterfly: Wingspan: 3½ – 4½ inches (8.9 – 11.4 cm). The upper surface of the forewing is mostly black with ivory spots along the margin. The upper surface of the hindwing has orange spots and a sheen of blue (female) or bluish-green (male) scales. The underside of the hindwing has pale green spots.
Spicebush Swallowtails add a splash of green to Alabama’s swallowtail color palate. Once known as Green-Clouded Swallowtails, males of the species were aptly named. Expanses of blue-green scales drift across their black hindwings, and green chevrons outline lower wing edges. Females also sport green chevrons, but their hindwing clouds are decidedly blue, making them excellent mimics of their poisonous relative, the Pipevine Swallowtail. They even flutter their wings when nectaring, also reminiscent of Pipevine Swallowtails. Although Spicebush Swallowtails butterflies look a lot like Pipevine Swallowtails, they are actually most closely related to Tiger and Palamedes Swallowtails. This becomes obvious when comparing their larvae: the family resemblance is remarkable.
Host plants verified in Alabama are Smooth Northern Spicebush (Lindera benzoin), Sassafras (Sassafras albidum), Red Bay (Persea borbonia), and Swamp Bay (Persea palustrus). The non-native Camphor Tree (Cinnamomum camphora) has also been documented but should not be planted in the landscape due to its invasive tendancies.
And they have some great ID info! Here is an example for the Spicebush Swallowtail. (Click on “Get Identification Help,” which is under the first thumbnail photo under the yellow section (i.e., in the off-white section).)
And in “Black Swallowtail Papilio polyxenes” they have a great ID tip! One that I have needed and have wondered about.
ID Tip: Black Swallowtails are often misidentified and confused with other large, dark swallowtails. Look for the dark body with a double row of creamy yellow dots. On both upper and under wing surfaces, look for an orange-red eyespot with a center black “pupil.” These are located at corner of the hindwings.
Again, click on “Get Identification Help,” which is under the first thumbnail photo under the yellow section (i.e., in the off-white section), to get some great ID info: