[Illustration: FIG. 2.--Representative Protozoa associated with cockroaches. A, _Monocercomonoides melolonthae_, × 3094 (after Grassé). B, _Coelosporidium periplanetae_, × 1310 (after Sprague); trophozoite with spores and chromatoid bodies. C, _Endamoeba blattae_, × 273 (after Kudo); trophozoite. D, _Lophomonas striata_, × 330 (after Kudo). E, _Lophomonas blattarum_, × 660 (after Kudo). F, _Retortamonas blattae_, × 3094 (after Wenrich). G, _Nyctotherus ovalis_, × 175 (after Kudo). H, _Gregarina rhyparobiae_, c. × 52: mature trophozoite attached to intestinal wall of _Leucophaea maderae_. (Redrawn from J. M. Watson [1945].) I, _Diplocystis schneideri_, c. × 14.4 (after Kunstler). J, _Gregarina blattarum_, c. × 57 (after Kudo). K, _Protomagalhaesia serpentula_, × 36 (after Pinto). L, _Gamocystis tenax_, magnification not known (after Schneider). (All figures except H redrawn from Kudo [1954] after sources indicated.)] Order POLYMASTIGINA Family CHILOMASTIGIDAE =Chilomastix mesnili= (Wenyon) _Experimental vectors._--_Blatta orientalis_ and _Periplaneta americana_, South Africa (Porter, 1918): The cockroaches were fed human excrement that contained cysts of _C. mesnili_. The cysts passed unharmed through the insects' digestive tract. Rats became infected with this protozoan on eating food that had been contaminated with feces from these cockroaches. Family POLYMASTIGIDAE =Eutrichomastix= sp. _Synonymy._--_Trichomastix_ [Kudo, 1954]. _Natural host._--_Blattella germanica_ and/or _Periplaneta americana_, South Africa (Porter, 1930). =Monocercomonoides globus= Cleveland et al. _Natural host._--_Cryptocercus punctulatus_, U.S.A., Appalachian and Pacific coast areas (Cleveland et al., 1934): Organism occurs in practically all hosts. =Monocercomonoides melolonthae= (Grassi) (Fig. 2, A) _Natural host._--_Platyzosteria novae seelandiae_, New Zealand (Laird, 1956): Found in the intestinal tracts of the adult cockroaches, and of other species of insects. =Monocercomonoides orthopterorum= (Parisi) _Synonymy._--_Trichomonas_ (_Trichomastix_) _orthopterorum_ Parisi; _Monocercomonas orthopterorum_ [Bělǎr, 1916]; _Trichomastic orthopterum?_ [Zasukhin, 1930]; _Monocercomonoides orthopterorum_ [Travis, 1932; Cleveland et al., 1934]; _Retortamonas orthopterorum_ [Semans, 1943]. _Natural hosts._--_Blatta orientalis_, Italy (Parisi, 1910); U.S.S.R. (Zasukhin, 1930). _Ectobius lapponicus_, Italy (Parisi, 1910). _Periplaneta americana_, Philippine Islands (Hegner and Chu, 1930). "Küchenschaben," Austria (Bělǎr, 1916). The protozoan is found in the hind gut. Zasukhin (1930) found the organism in 85 percent of over 3,000 _B. orientalis_. Parisi (1910) found the flagellate present in very large numbers. =Monocercomonoides panesthiae= Kidder _Natural host._--_Panesthia angustipennis_, Philippine Islands (Kidder, 1937): In hind gut. =Tetratrichomastix blattidarum= Young