The colorful nymphs on this page are Neotropical members of subfamily Phaneropterinae, perhaps in or near genus Scudderia.
Location for the first photo on this page: Along the Rio Negro, Amazonas state, Brazil.
Next two photos below: Along the Rupununi River, Guyana
Two photos below: Rewa Village, Guyana
Location for the photo below: Pico Bonito National Park, Honduras
American Insects site