They are found everywhere except in oceans and near the poles, and they occupy nearly every kind of habitat. Most are terrestrial, but some are underground tunnelers and some live in water. These water beetles are often confused with water bugs, but the latter all have sucking mouthparts. Most are dull, but members of several beetle families are brilliantly colored, some with a metallic or iridescent sheen. The majority of beetles are plant eaters, but there are also many predators and scavengers and a few parasites.
Weevils are plant-eating beetles with mouthparts elongated into snouts bearing jaws at their ends.
The fireflies are luminescent beetles. Blister beetles , including the so-called Spanish fly, produce irritating secretions. Beetles are classified in the phylum Arthropoda , class Insecta, order Coleoptera. The Columbia Encyclopedia, Sixth Edition. Click here to shop the Bartleby Bookstore .