Crop circles! This odd assemblage is actually a group of spiraling whitefly nymphs (Aleyrodidae), who secrete a white, waxy substance responsible for the long hairs and eerie outline. (Panama)
Assassin bug (Reduviidae) from Panama.
Assassin bug nymphs, Reduviidae, from Panama. There were several groups of them on this particular tree trunk at varying stages of development, but they were only detectable upon close examination. From a short distance, they quickly became practically invisible against the bark.