"The Hemiptera are called 'true' bugs because everyone - entomologists included - tend to call all insects 'bugs'."
"Many of them are very different from each other, but all of them have piercing mouthparts with which they can suck the juices from plants or animals - usually plants. Their mouthparts are contained in a beak (or rostrum) which is usually held underneath the body when not in use."
"As plant feeders, some bugs - such as the aphids, for example - are serious agricultural pests, not just because they damage crops but because they can transmit viral diseases too. However, most bugs are not pests."