Stock Photo - Cockroach. Cockroaches (or simply ´roaches´) are insects of the order Blattodea. This name derives from the Latin word for ´cockroach´, blatta. Cockroaches are generally omnivores. An exception to this is the wood_eating genus Cryptocercus, with various species found in Russia, China, Korea and the United States. Although they are incapable of digesting the cellulose themselves, they have a symbiotic relationship with a protozoan that digests the cellulose, allowing them to extract the nutrients. In this, they are similar to termites and current research suggests that the genus Cryptocercus is more closely related to termites than it is to other cockroaches. Cockroaches are most common in tropical and subtropical climates. Some species are in close association with human dwellings and widely found around garbage or in the kitchen.