21 Else, if thou will not let my people go, behold, I will send swarms of flies upon thee, and upon they servants, and upon thy people, and into thy houses. And the houses of the Egyptians shall be full of swarms of flies, and also the ground on which they are.
Exodus 8:21 Cross References - ACV
Psalms 78:45
45 He sent among them swarms of flies, which devoured them, and frogs, which destroyed them.
Psalms 105:31
31 He spoke, and there came swarms of flies, and lice in all their borders.
Isaiah 7:18
18 And it shall come to pass in that day, that LORD will whistle for the fly that is in the outermost part of the rivers of Egypt, and for the bee that is in the land of Assyria.