Yes, our mystery insect last week was actually the exoskeleton or the shed "skin" of a dragonfly nymph.
Dragonfly nymphs usually live under water, but they crawl onto land before emerging as adults. Exposure to the air and sun has darkened this exoskeleton and made it look, well, crispy.
You can tell the adult dragonfly has emerged because of the opening in the back of the thorax. Those white lines are the remnants or linings of the breathing tubes (tracheae) that pull out as the adult dragonfly emerges. The adult will produce new tracheae.
The one feature that really tells that this is a dragonfly nymph is the head, particularly the "mask" at the bottom of the face. Dragonfly nymphs have a special lower lip or labium that they use as an "insect net." It not only shoots out to capture or scoop up prey, but also holds food while they eat, sort of like a horse's feed bag.
In this video of a live dragonfly nymph feeding, look for both uses of the labium.
Isn't that cool?
I loved reading all the imaginative ideas about what the insect might be. Would you be interested in future mystery insects?
If you would like more dragonfly science, try this previous post with activity ideas.