Yes, I am a literalist. So the question is: When I read those chapters, I ask myself the question, what did John really see when he was transported to heaven? What was he trying to describe.
I will give you an example. Quite a few years ago I was on the mission field for a lengthy period of time with my family. CD players had not yet been invented when I left. We used cassettes. If you had told me before I left that when I came back I would be listening to music from a machine that: "would use flashing laser lights to record and read back information from the shiny metal discs...the only thing that touches the CD is a beam of
light: the laser beam bounces harmlessly off the surface of the CD, so the disc itself should (in theory) never wear out.
http://www.explainthatstuff.com/cdplayers.html " Now if you had told me something like that I would say that you were crazy and out of your mind. That is mind-boggling. Yet when I came home, that is exactly what was happening.
John didn't have the vocabulary to describe what was in heaven; what he was seeing. He describes it with the vocabulary he has, especially when seeing things like locusts. What were they? I don't know. Maybe they were supernatural giant locusts created for a specific purpose by God, or perhaps he saw some modern warfare that looked like it. I don't know. I don't speculate. I only know the result.
Shortly after we read:
Rev 9:10 And they had tails like unto scorpions, and there were stings in their tails: and their power was to hurt men five months.