This little (4mm) potter wasp (Eumeninae) built the cells she will use to rear her young on an abandoned length of fishing line. In this photo, she was still building the cells, laying eggs, or provisioning the cells. It was night and she had clamped onto the line with her mandibles to rest. Many wasps and bees do this when they rest.
Pretty sure this thorn hopper is in the genus Umbonia. These lovelies are quite common.
This photo shows an 8-9mm Costa Rican trap-jaw ant with her jaws in the open position. Her genus is Odontomachus. If you stretch or enlarge the photo, you can see the tiny setae arrayed along the inside of the jaw. Her jaws will slam shut if these hairs come into contact with prey. I frequently see these ants (as well as another species of trap-jaw) in the forest. They move slowly by ant standards and are relatively easy to photograph.
