When disturbed, a Papilio polyxenes swallowtail larva everts its osmeterium, a foul-smelling defensive organ located behind the head. Urbana, Illinois, USA
Papilio polyxenes - eastern black swallowtail - caterpillar with defensive osmeterium everted. Urbana, Illinois, USA
Danaus plexippus - monarch butterfly taking nectar from a fall-blooming aster. Urbana, Illinois, USA
