Northern Prairie Wildlife Research Center
First 3 instars resemble bird-droppings: shiny green-brown to chocolate brown with black eyespots on thorax and variously developed white spiracular stripe that may be all but absent, or more commonly, enlarged to form a saddle that curves up over third and eighth abdominal segments. Last 2 instars snakelike, green, yellow, or yellow-orange, with large "pupiled eyes" on third thoracic segment, followed by paired yellow spots on first abdominal segment, and conspicuous blue spotting. Body yellow or reddish tan below broad yellow spiracular stripe. Palamedes swallowtail (P. palamedes) closely similar but with white spot in both pairs of eyespots smaller or absent, and more rusty or maroon beneath; caterpillars on red bay and sassafras. Food: sassafras, spicebush, magnolias, and red bay. Caterpillar: April to November; 3 generations in South, 2 in North.