Perhaps the most famous quote about beetles comes from the great population geneticist J.B.S. Haldane, who was asked what might be learned about a Creator by examining the world. Beetles are holometabolous insects, normally with adecticous, exarate pupae. Most species have chewing mouthparts. There is a gula present on the undersurface of the head. The four living suborders of beetles diverged from one another in the Permian and early Triassic, and are substantially different from one another.
Adults differ in the structure of the prothorax, hind wing, abdomen, ovary, testes, and so on.
The major differences are summarized in a table . Many are phytophagous. Myxophaga is a small suborder, containing less than 100 known species, whose members are small or minute, and associated with hygropetric habitats, drift material, or interstitial habitats among sand grains. There are several competing hypotheses regarding subordinal relationships. The composition of the clade Coleoptera is not in dispute, with the exception of the twisted-wing parasites, Strepsiptera.