Caterpillars

The Giant Swallowtail is an impressive butterfly of the southern U.S. that that wanders quite widely in late summer. It strays into and sometimes breeds in Wisconsin. The upper surface of the wing is black with a dramatic, yellow stripe, and the underwing is yellow, which gives it a confusing appearance in flight. When Giant Swallowtails do breed here, the food plant of the caterpillar is Prickly ash, which is the northern-most member of the citrus family.