The Hemiptera order includes bed bugs, diving beetles and water bugs, whose back wings are horny at the base and membranous at the extremity. It also includes insects whose wings are completely membranous, such as cicadas, spittlebugs, treehoppers, psyllids and aphipds. Some, like bedbugs, lost their wings over the course of evolution.
In the large Coleoptera order, two pairs of wings are completely different from each other. The first pair, called elytra, are thick, horny and sometimes very colourful. They cover the two membranous wings, protecting them like a shield or case (Coleoptera means “wing case”). When the insect takes flight, the elytra lift up so the membranous wings can be used for flight. They act as a flight stabilizer.