Canopidae and Megarididae are two small families found only in the Neotropics. A 1979 article in the Journal of the New York Entomological Society had this to say about the evolution of the two families:
"The Megarididae are very primitive and are probably an early offshoot from the Pentatomoid line of evoution. The Canopidae are more highly evolved and show some affinity to the Scutelleridae" (MacDonald, 1979).
Photo location: Along the Rewa River, Guyana.
American Insects site