These are two Ceratomia catalpae (catalpa worms/sphinx) that I took as second instars and raised myself. They just burrowed in order to pupate today, two days after this picture was taken. C. catalpae seem to be very picky when it comes to temperature. They would not feed on their provided leaves indoors at 72 degrees, however, started gobbling it down once they were place back into 90 degree heat! Very interesting critters.