Insects are the most numerous class of animals. More than 1 million species are described (and more than 7 thousand new species are described each year), but in nature there are many more – from 2-3 to 7-8 million species. Fascinating that for each person comes several hundred million insects.
They represent small organisms (from 0.2 mm to 30 cm) belonging to the type of invertebrate arthropods. The insects get their name from the notches on their bodies, which are due to the chitinized cuticle that covers their bodies (although this is not true of every species).