These insects may well have drawn attention to themselves. The name 'stink bug' is mostly an American use. The French call them punaise which means much the same, though this is a general term, used for many kinds of bugs including bed-bugs. The word is also the French for 'drawing pin'. But there is a connection. All bugs have needle like mouth parts which can draw blood, and so can a drawing pin. Bugs are very different from flies and beetles, even if the non-expert person often muddles them. If they were flies, the wings would be membranous and exposed without any covering. If they were beetles, there would be a line down the middle separating the two cases which protect the wings either side. But with bugs the wings overlap and moreover the first pair of wings are curiously formed. These are half rigid and half membranous. In the shield bugs there is also a large triangular armoured patch on the back (the scutellum) between the wings. Since the right and left wings overlap when they are at rest, altogether a pattern of triangles appears on the back. In the centre is the triangle formed by the scutellum. At each side are triangles formed by the hard parts of the fore wings and at the rear remains a more irregular area where the soft parts of all the wings overlap. The exposed abdomen makes a patterned border at the sides.
The broad shoulders of the thorax enhance the shield shape of these insects. Many of them are colourful and often beautiful.
Many are pests of plants sucking at the sap and weakening the plant. In winter they usually hibernate in the adult stage, hiding, sometimes in some numbers together, in wood piles or in cool corners of the house. When they emerge from dormancy they buzz noisily around the lights and become a nuisance even though they are harmless. If you annoy them they often emit a strong smell. That is why they are called stink bugs The stink glands are on the under side of the thorax so if you press your finger gently on the back the gland is compressed and the smell is emitted. The insect shown here (Rhaphigaster nebulosa) smells strongly of almonds with a sour element - bitter almonds is the description. The smell is identical to the smell of prussic acid or cyanide. If it is that, then they would be lethal to predators. The books often say that the smell of shield bugs is 'soapy'. It is also claimed that the smell attracts individuals to group together. That seems unlikely to me. I wonder if different species have different smells?