Sorry, no pics, but I wonder if anyone can take a stab at an identification from a description.
I was recently in Mexico, on the Caribbean coast (near Tulum). In several places I noticed what I first took to be some form of beetle clinging motionless to the legs of wooden chairs on the beach, to the base of palm tree trunks, and to the outside walls of cabanas, within a few inches of the ground. On closer inspection, though, they seemed to be some kind of empty chrysalises, attached to said objects via six (I think) distinct “legs” rather than just at one point, giving the beetle-like appearance. The casings were light brown, about an inch long, and each had a lengthwise split on its “back” where whatever was inside had exited.
Any ideas what they might have been?
Cicadas, sounds like.
Did they look anything like this:
(warning, grotesque bug pic)
http://images.whatsthatbug.com/images/cicada_exoskeleton_jr.jpg
They are definitely Cicadas.
Yep, those were the beasties. Curiosity satisfied, thanks!
BTW I just had a look at the Wikipedia page and there’s a cool animated gif of a cicada emerging! Freaky… 
(Edit: Looks like they’re pretty ubiquitous creatures; surprised I have never noticed the exoskeletons anywhere else on my travels…)
I think it’s often the case that they only emerge en masse every x years (where x is a prime number, usually) - so it may be that you’ve been to other places where there would be lots of them but they were just not about when you went.
Only certain species of cicada emerge in such lengthy cycles. Others can be seen (and definitely heard) annually.
You needn’t go as far South as Mexico- my yard is filled with those shells every year.
They’re fun to throw at your sister and watch her scream. At a certain age, anyway.
I am in western Pennsylvania and see them sporadically. This weekend I was surprised to see 5 of them on a small weeping willow tree I planted last year.
I grew up seeing those all the time, every summer, in NE Ohio. Still do, although not as often. Their song is one of the sounds of summer that I just couldn’t do without.