​BLATTA, a genus of insects, the typical one of the family blattidæ. It contains the various species of cockroaches. B. orientalis is the common species in houses in the southern portions of the United States, though, as its name implies, it is believed to have come first from the East. In the higher latitudes of the United States B. orientalis is rarely or never seen, its place being taken by B. americana, or the kakerlac, as it is called.