Abstract
The amounts of carboxymethyl cellulase present in the midguts and hindguts of two species of cockroaches were determined. Numbers of colonies from the guts which digested carboxymethyl cellulose, visualized by flooding plates with cetyltrimethylammonium bromide after incubation, were counted. The numbers indicated the presence of a resident, multiplying population of predominantly anaerobic carboxymethyl cellulose-digesting bacteria in both species of cockroaches. Anaerobic and facultatively anaerobic species of bacteria were isolated, and their carboxymethylcellulase activities were assayed.