Holometabola, insects with complete metamorphosis, account for more than 80% of insect species and more than 50% of all animal species. Holometabola is the most diverse and successful group of terrestrial organisms. Holometabola is comprised of 11 insect orders, four of which – Coleoptera, Hymenoptera, Diptera, and Lepidoptera – account for over 99% of the species diversity of this group. Mecoptera, Strepsiptera, Megaloptera, and Raphidioptera each contain less than 1000 described species, and Trichoptera, Neuroptera, and Siphonaptera each contain less than 4000 species. Research is underway to decipher the phylogenetic relationships among these orders, and resolve some outstanding issues such as identifying the sister group to Hymenoptera. Click here to see some publications on holometabolan phylogeny.