Monarch Caterpillar
Danaus plexippus

f25 @ 1/320s, ISO:2000, Nikon D3S w 105mm macro

"Monarch Butterfly," Wikipedia, the free encyclopedia. The larva (caterpillar) has five stages (instars), molting at the end of each instar. Instars last about 3 to 5 days, depending on factors such as temperature and food availability. The third-instar larva has more distinct bands and the two pairs of tentacles become longer. Legs on the thorax differentiate into a smaller pair near the head and larger pairs further back. Third-instar larvae usually feed using a cutting motion on leaf edges. The third instar is usually between 1 and 1.5 cm long.
Francis A. Crane Wildlife Management Area, East Falmouth, Massachusetts