This is a Red-Footed Cannibalfly (Promachus rufipes), eating a Common Green Bottle Fly (Lucilia sericata). They feed on bees, wasps, dragonflies, spiders, beetles, grasshoppers, and other flies. They have a venomous saliva that allow it to easily subdue prey that may be larger than itself. The saliva contains chemicals that dissolves the inside of a victim, in preparation for them to be sucked out. They are also known as; Robberfly, Robber Fly, Assassin Fly, or Bee Panther.
A Mydas Fly (Mydas clavatus) on a Rattlesnake Master (Eryngium yuccifolium) wildflower in Indiana. They are a wasp mimic. In the Midwest the rattlesnake master is a favorite nectar source for this insect. It is also known as a clubbed mydas fly. The Midas fly, has a golden band across its abdomen, and for that reason it was named for the Phrygian king Midas.