Milton uses a simile comparing night to the swarm of locusts hovering over Egypt. This reference to night also implies a dark setting that sets a dark tone. The image of the angels swarming is described as being so thick and cast that it appears as night falling over the land. This comparison conveys the angels as dark and evil, and further exemplifies the angels as creating an even darker scene in hell, by swarming into an assembly. They are also compared to night because Chaos is compared to night. Chaos spreads from the realm of hell to earth. Milton equates the mass of fallen angels to Chaos, and the concept of evil.