Common tree cricket, Oecanthus sp., from the Timucuan Preserve in Jacksonville, Florida. This is likely the genus of tree crickets responsible for Dolbear's Law - that is, the equation showing that ambient temperature can be reliably calculated by how frequently a cricket chirps. Try it for yourself: the next time you hear a cricket chirping, count how many chirps you hear in 15 seconds and add 40 to get Fahrenheit (for our Celsius friends, count how many you hear in 8 seconds and add 5) - it should be pretty close!
Meadow katydid (Conocephalinae: Conocephalini) from Iowa.
A distinctive grasshopper, probably Romaleidae, from Costa Rica.