1. The Protozoa from the hindgut of the wood-feeding roaches Panesthia javanica and P. spadica are described.
2. These Protozoa are to be regarded as commensals.
3. They belong to three subphyla of the phylum Protozoa.
4. Two are flagellates, Monocercomonoides panesthiae sp.nov. and Hexamita cryptocerci Cleveland.
5. Two species of Endamoeba are described, E. philippinensis sp.nov. and E. javanica sp.nov., the former small and a bacteria feeder, the latter large and xylophagous.
6. An unidentified amoeba was observed in one roach.
7. Nyctotherus uichancoi sp.nov. was found in the majority of Panesthia javanica and infrequently in P. spadica.
8. Nine species of heterotrichous ciliates (Clevelandia gen.nov. and Paraclevelandia gen.nov.) make up the family Clevelandiidae fam.nov.
9. This family is characterized by the posterior position of the mouth which may occur at the end of a projection, varying in length. It is closely related to the family Plagiotomidae, to which Nyctotherus belongs.
10. A well-integrated neuromotor system is described in the family Clevelandiidae, being practically identical in all members.
11. The relationships of Panesthia, Cryptocercus, the domestic cockroaches, and the termites are discussed on the basis of their protozoan faunas.