Butterfly in flight above whorled milkweed plants with black forewings marked on the underside with one row each of yellow triangles and circles near the trailing wing margin. The hind wing also bears two parallel rows of yellow marks, but with intervening blue polygons and conspicuious tails. The body is also black with yellow spots along the side of the abdomen.

Butterfly in flight approaching a whorled milkweed plant in bloom with black forewings marked on the underside with one row each of yellow triangles and circles near the trailing wing margin. The hind wing also bears two parallel rows of yellow marks, but with intervening blue polygons and conspicuious tails. The body is also black with yellow spots along the side of the abdomen.

Butterfly in flight just before contacting a whorled milkweed plant with black forewings marked on the underside with one row each of yellow triangles and circles near the trailing wing margin. The hind wing also bears two parallel rows of yellow marks, but with intervening blue polygons and conspicuious tails. The body is also black with yellow spots along the side of the abdomen.

Butterfly resting on a whorled milkweed plant with black forewings marked on the underside with one row each of yellow triangles and circles near the trailing wing margin. The hind wing also bears two parallel rows of yellow marks, but with intervening blue polygons and conspicuious tails. The body is also black with yellow spots along the side of the abdomen.

Coming in for a landing! Black #swallowtail #butterflies, #Papilio #polyxenes, approaching & landing to nectar on whorled #milkweed, #Asclepias verticillate, in central #Illinois, #USA

Orange, white, and black-marked 2nd instar black swallowtail caterpillar with prominent spiny-tipped tubercles, dangling from the jaws of a brown crab spider.

Orange, white, and black-marked 2nd instar black swallowtail caterpillar with prominent spiny-tipped tubercles, dangling from the jaws of a brown crab spider.

Orange, white, and black-marked 2nd instar black swallowtail caterpillar with prominent spiny-tipped tubercles, dangling from the jaws of a brown crab spider.

Orange, white, and black-marked 2nd instar black swallowtail caterpillar with prominent spiny-tipped tubercles, dangling from the jaws of a brown crab spider.

Now just another link in the food chain. The black #swallowtail #caterpillar, #Papilio #polyxenes, that was feeding for >1 wk on my golden alexanders, #Zizia aurea, met its demise in the clutches of a crab #spider this evening. Caterpillars are “kibble” for many #predators.

Orange, white, and black-marked 2nd instar black swallowtail caterpillar with prominent spiny-tipped tubercles twists its body around the green stem of a golden alexandar flower. Its head is at the top of the image.

Orange, white, and black-marked 2nd instar black swallowtail caterpillar with prominent spiny-tipped tubercles with its body arching on and over the green flower head of a post-flowering golden alexandar. Its head is at the top of the image.

Orange, white, and black-marked 2nd instar black swallowtail caterpillar with prominent spiny-tipped tubercles with its body arching on and over the green flower head of a post-flowering golden alexandar. Its head is at the top of the image.

“Doing the twist.” A 2nd instar black #swallowtail #caterpillar, #Papilio #polyxenes, dining on a golden alexanders, #Zizia aurea, #flower. The coming instars will give up their resemblance to bird droppings and become more green & harder to find in dense vegetation.

Orange, white, and black-marked 2nd instar caterpillar with prominent spiny-tipped tubercles grips a green stem. It is facing the crumpled black and orange remnants of its 1st instar exoskeleton.

A black #swallowtail #caterpillar, #Papilio #polyxenes, has just molted to the 2nd instar on a golden alexanders, #Zizia aurea, flower. It's staring down what remains of it's old skin before consuming the rest.