The “clean insects” are the locusts that are basically swarming grasshoppers. Cicadas don’t exist in the middle east, so they aren’t mentioned in the Bible.
The Bible gives us guidelines for clean and unclean animalsm. In a nutshell, if you look at the commonalities of what comprises clean meats and unclean meats, as close as possible, vegetarian animals that are not scavengers are considered clean.
Unless you can show me that cicidas are insect carnivores or scavengers, I think they fit the Biblical guidelines of what would comprise a clean insect.
Did you buy enough butter?