ZOOLOGY A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site insect A member of the class Insecta, which is in the phylum Arthropoda (see arthropods). This class contains organisms that in the adult normally have six legs, three distinct regions to the body (head, thorax, and abdomen), one pair of antennae, and, often, one or two pairs of wings. Most insects are terrestrial and breathe through a system of tubes called tracheae. Insects include butterflies, beetles, bees, ants, spring-tails, silverfish, cockroaches, earwigs, termites, flies, aphids, lice, and fleas. More than one million different species are known out of a global diversity estimated at 10 million insect species. Of the 32 orders into which insects are classified, the largest is the beetles, or coeloptera, with 125 different families and around 500,000 species. Related category    • ZOOLOGY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP