My milkweed is covered in little tiny almost-spherical yellow things about 1 to 1.5 mm in diameter. They have black legs that were too small for the camera to see. I think they might be fly larva, because I saw a similar looking bug nearby with wings. The bug in the picture is a completely featureless yellow thing except for the legs, which look like black cactus needles. I say they're bugs, but only because they move. They don't really look like bugs to me.
Anybody know what these are? Are they damaging the plants?