This one was surprisingly straightforward to identify. The lack of a sclerite at the base of the lateral hump narrows the field quite a bit, and the other options followed fairly obvious characteristics to Clostoeca, which only has one species, Clostoeca disjuncta.
Delvalle on Jul 11, 2008July 11th, 2008, 9:00 am EDT
I could use help identifying this insect. I scooped it off a lily pad on a small lake in NW lower Michigan. I noticed these insects appear on the water surface usually between 6:00 am to Noon. The nymph was also on the same lily pad. Additionally, there is a similar insect on the same lake much like this one. However, the thorax and tail are blue in color. (Sorry, I do not have photo of the blue insect.) Are these damsel flies or Mayflies? Sorry for the questionable quality of the pictures. I am new at this and still learning. Thanks.
Your photographs are of an adult damselfly, and two abandoned damselfly nymphal shucks. In their nymphal form, the damselflies likely crawled up the stalk of the lily pad to above water level, which would only be achieved once on top of the pad, and then proceeded to depart their nymphal shucks, and fly away. Of course, it's also possible that one of the abandoned shucks belongs to the adult, and it hadn't yet taken flight.