The one's that scare me are the Mud Daubers that are an almost a metallic purple in color. And they flicker their wings while they decide on who and when they're going to sting.
Psychological Warfare, Bill. The young are intensively trained in this technique. It instills fear in the prey causing an adrenaline dump which, in turn, causes and increase in the victim's heart rate and, thus, blood flow which has the effect of spreading the venom much faster through your body Bill...