You might be startled to learn that there are nearly 100 species in the cockroach order in North America north of Mexico. A great majority of cockroaches and termites are not pests to people. Only a few species are pests in homes, and many of these originally came from the Old World, having traveled around the globe with people. The rest are humble decomposers that live under rocks, bark, rotting wood, or leaf litter and never enter homes.
Most people know a typical cockroach when they see one: they are flattened, oval, usually small, with long, swept-back antennae, colored reddish brown, brown, or black, and often shiny. They usually have a pair of antenna-like cerci at the end of the abdomen. They can hide in tight crevices and lack specialized appendages or mouthparts. Those with wings fold them overlapped over their back.
Some typical cockroaches in Missouri include various species of wood cockroaches (Parcoplatta spp.), which live in wooded areas and rarely enter homes, as well as common household pests such as the German cockroach (Blattella germanica) (originally from northeast Africa or southeast Asia), American cockroach (Periplaneta americana) (originally from tropical Africa), and Oriental cockroach (Blatta orientalis) (originally from the region between Europe and Asia).
Recently, termites have been included in the cockroach order, making the combined cockroach-termite order, as a whole, more difficult to describe. The families of termites are clearly different from the families of typical cockroaches.
Termites, which used to be separated in their own order (Isoptera), have been folded into the cockroach order based on DNA evidence: They are closely related to one of the families of cockroaches, so all share a common ancestor. In North America, there are five families (about 50 species) of typical cockroaches and four families (about 50 species) of termites.
The various families of termites are grouped together is an epifamily, Termitoidae, which recognizes how distinct they are from the typical cockroaches in the cockroach-termite order.
People often confuse termites with ants. Both are small insects that live in colonies and live on or near the ground, under rocks, wood, and leaf litter. Ants, however, have the middle part of the body narrowed to a relatively tiny stalk between the large head and the large abdomen. Termites, however, have a fairly cylindrical body, only slightly narrowed behind the head. Ants lack a pronotum (a shieldlike plate behind the head, where their shoulders would be), while termites and cockroaches have a pronotum.