What's this?

We were storing away some garden furniture today (seemed prematurely even for second half of November when the sun is still shining so fiercely that our cocker Diva has spent the afternoon basting on the balcony, always with an eye on the small valley below because it's the day of 'La Chasse'), when we found this:

She-who-must-be-obeyed-and knows-everything believes it is the discarded carapace of a cicada. Opinions from people more expert will be most welcome. We curse the cicadas sometimes in the summer: one starts up and within minutes another half dozen are sirening away. We sometimes confuse their noise with the calls of a couple of tree-frogs who live in our garden - very beautiful little critters, like bright green enamelled gems.