Bugs (Heteroptera) are a suborder of insects that, like the suborders of cicadas and plant lice respectively, are part of the overarching order of Hemiptera. This classification is not entirely uncontroversial, because cicadas probably descend from bugs, and their group can therefore not be seen as an equal suborder alongside bugs.
Bugs are usually small insects; most species are smaller than a centimetre. They initially have four wings, but in some species these are reduced. Bugs have an incomplete metamorphosis. They differ from other groups of insects in that they have tubular mouthparts with which they suck up food.
Some species, such as the bed bug, are known as pest insects that also occur indoors. A number of species cause damage to agricultural crops, but less destructive than, for example, plant lice or grasshoppers. The males of many bug species can produce sound, just like grasshoppers, thanks to – different for each species – adaptations to the body. The females and larvae of certain bug species also make buzzing sounds. Thanks to hair-like senses on their antennae, bugs can perceive sound vibrations.