This little green tree cricket was only about an inch long and looked just like a leaf until you got close enough to see that it wasn't a leaf after all. Like other species of cricket they produce their calling song by rubbing the ridges of their wings together. The chirp (or trill) of a tree cricket is long and continuous and can sometimes be mistaken for the call of a cicada or certain species of frogs.
While male tree crickets have the ability to call, females lack the ability. This call is then received by other tree crickets in the area through a system called sender-receiver matching. For example a male tree cricket will produce a mating call at a specific range of frequencies. This allows females to be able to pick out the males mating call without becoming distracted or confused by other calls from other species of insects.
This range of frequencies is called a carrier frequency. Tree crickets are unique in the way they use carrier frequencies due to the fact that the range of frequencies changes according to the temperature. Female tree crickets seem to prefer calls at the lower range of frequencies indicating the presence of a large male. Photo Copyright 2010 Robert Giordano.
Description from Wikipedia