Potter wasp, Eumenes fraternus (Eumeninae) from Iowa.
Winged queen weaver ant (Oecophylla smaradigna) from Cambodia.
A common sight among foraging leafcutter ants (Atta cephalotes) in Costa Rica is a smaller ant, known as the minima caste, riding on top of the foraged item being carried by a larger worker. While it might appear that they are simply hitching a free ride, in fact they are providing an important service - protecting their sisters from opportunistic parasitic flies (Phoridae) that attempt to deposit eggs on them.