Hello larry. I'm pretty sure these are sticky pollen things - maybe packet is the wrong word to describe them, but these sticky yellow sacs get all over them - even on their heads and forelegs as they wander around on milkweed flowers right at the time when these plants are oozing with pollen and nectar. I've seen them with several stuck all over them - feet, heads, forelegs, and they spend quite a bit of time trying to clean themselves off - like a bird preening. That happens to other insects that land on milkweed at that time. I've actually seen flies and bees with so many of these sacs stuck to them that they are unable to fly and are actually stuck to the flowers and sometimes die. Here's a photo of a mantidfly that has them on its head and a foreleg.
http://www.pbase.com/crocodile/image/73492885 Thanks for mentioning the word arolium though as it was an unfamiliar term to me. -bev
