With something in the region of a quarter of a million species, the beetles are by far the largest group of insects. Rather more than 4,000 species are known in the British Isles but, although many of them turn up in the garden from time to time, very few are in any way restricted to garden habitats.

Beetles are generally recognised very easily because the front wings are hardened and modified into protective shells called "elytra". These elytra usually cover the whole abdomen, but they are very short in "Rove Beetles" and they are absent altogether from the female "Glow-worm". Only the hind wings are used for flight, but most beetles prefer to keep their feet firmly on the ground or on the vegetation and they don't very often fly. They scuttle away when disturbed, or else they just drop to the ground and play possum (lie still), with their legs held tightly against the body. Many beetles have no hind wings at all, and their elytra are fused together and immovable. It is possible that some of the beetles will be confused with the "Heteropteran bugs" to start with, but the elytra of the beetles always meet and form an obvious junction in the mid-line, whereas those of the bugs always overlap. In addition, the beetles all have biting jaws and never have the piercing beak which is so obvious in the bugs.