Have you seen many of these? They are called a cicada -
This is the noise that a lot of them make! - That noise that you hear on the video above is real and no I have not turned the volume up!
"They make this sound by flexing their tymbals, which are drum-like organs found in their abdomens. Small muscles rapidly pull the tymbals in and out of shape — like a child's click-toy. The sound is intensified by the cicada's mostly hollow abdomen." i information from http://www.cicadamania.com/
These pictures are actually not the cicada, although I thought that they were initially!
This is actually what they are - the skin which remains after the molting of the cicada!
We saw these on our trip to Ko Yao Noi.