I spy with my little eye

I find these critters disgusting, however the outward complexity of a compound eye is still something to behold. The way they work is simplicity itself, all they perceive is change in tone. Which leads to a top tip if you want to catch them and stop them from buzzing about your house. Place a piece of white paper either side and close in. They are not able to notice the movement as there is no change in tone. Its up to you whether you squash together or carefully fold at the end to remove the little critters!