Exodus 8:21

For if you do not let my people go, see, I will send clouds of flies on you and on your servants and on your people and into their houses; and the houses of the Egyptians and the land where they are will be full of flies.

Psalm 78:45

He sent different sorts of flies among them, poisoning their flesh; and frogs for their destruction.

Psalm 105:31

He gave the word, and there came the dog-fly, and insects over all the land.

Isaiah 7:18

And it will be in that day that the Lord will make a piping sound for the fly which is in the end of the rivers of Egypt, and for the bee which is in the land of Assyria.

Treasury of Scripture Knowledge

Summary

Else, if thou wilt not let my people go, behold, I will send swarms of flies upon thee, and upon thy 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 whereon they are.

Bible References

Swarms

Psalm 78:45
He sent different sorts of flies among them, poisoning their flesh; and frogs for their destruction.
Psalm 105:31
He gave the word, and there came the dog-fly, and insects over all the land.
Isaiah 7:18
And it will be in that day that the Lord will make a piping sound for the fly which is in the end of the rivers of Egypt, and for the bee which is in the land of Assyria.

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain