The largest major group of arthropods is a clade that includes insects, millipedes, centipedes, and their relatives. This group, the Uniramia, was formerly defined to include the Onychophora, which are now considered a separate clade. It is restricted here to include only "true" arthropods with exoskeletons and jointed appendages.
Uniramians have strictly uniramous appendages; that is, their legs have only one branch. Most are terrestrial, but some are aquatic for part or all of their life cycles. They make up by far the most common and diverse major clade of arthropods, and in fact make up over three-fourths of all known animal species on the planet -- and probably an even greater proportion of the total number of species, known and unknown. As the paleontologist J. Kukalová-Peck once put it: To a first approximation, every animal is an insect. Think about that the next time you call Orkin Pest Control.
Click on the buttons below to learn more about the Uniramia.
There is an immense amount of entomological information on the WWW. Click here for a list of servers pertaining to insects and other uniramians, courtesy of the Department of Entomology at Colorado State University. Or click here for recipes.