|Photos by Ned Harris 11/13/2012|
What ARE this things? I'm glad you asked! They are nymph and adult Keeled Treehoppers [link is to a photo by Margarethe Brummermann; who will be at the 4th Avenue Street Fair - 7-9 December, 10am-dusk - with her wonderful watercolor art - booth #626].
The nymphs are in various stages (like all insects, they have to shed their exoskeleton to grow); you can see them most clearly in the top photo. The adults have keels, which scientists think are actually fused wings (thus not breaking the 'rule' that adult insects have wings : -)
The herds pictured were all over Sacred Datura (Datura wrightii) plants in the riparian area by the dam. (You know that fruit, too.) These are the same type of bugs that eat other plants in the Solanaceae family - like tomato plants.