List of animal phyla
Hexapoda. Two classes of hugely different size. Insecta: the insects;p196 overwhelmingly the most common terrestrial animals, with an estimated 1.5 to 3 million species in about 30 orders. Apterygota are the wingless insects. Development of insects involves many kinds of larvae, both aquatic and terrestrial and, almost always, metamorphosis. The other class, the Entognatha consists of three small groups.