Creeping water bug, Naucoridae, from Panama.
A 'nursery' of recently-hatched 1st- and 2nd-instar stink bug nymphs, possibly the nefarious 𝐻𝑎𝑙𝑦𝑜𝑚𝑜𝑟𝑝ℎ𝑎 ℎ𝑎𝑙𝑦𝑠, in Iowa.
Red-Cross Shield Bug, Elasmostethus cruciatus, from Wisconsin. (Harry Potter fans will recognize that species name, coming from the Latin for "crossed.")