_Natural host._--_Cryptocercus punctulatus_, U.S.A. (Yarwood, 1937): This intracellular parasite was found in the fat body in light infestations. In heavy infections the coccidia were found in the head, antennae, mouthparts, muscles, legs, salivary glands, nerve cord, as well as fat body. Infection in freshly collected specimens was about 3 percent; when large numbers of cockroaches were kept together in culture, the rate of infection increased because the insects ate their dead companions. Cleveland et al. (1934) mentioned a coccidium which was sometimes generally distributed through the body (head, legs, antennae, etc.) of _C. punctulatus_; this parasite was probably the species described by Yarwood. Order HAPLOSPORIDIA =Haplosporidium periplanetae= Georgévitch _Natural host._--_Blatta orientalis_, Yugoslavia (Georgévitch, 1953): This organism was described from the malpighian tubules of the cockroach where it apparently occurred in a mixed infection with the microsporidian _Plistophora periplanetae_. See synonymy under _Plistophora periplanetae_. =Coelosporidium periplanetae= (Lutz and Splendore) _Synonymy._--_Nosema periplanetae_, _Coelosporidium blattellae_, _Bertramia blatellae_ [after Semans, 1943]. Some of the observations cited under _Plistophora periplanetae_ may pertain to _C. periplanetae_ (see Sprague, 1940). See also _Haplosporidium periplanetae_. _Natural hosts._--_Blatta orientalis_, U.S.S.R. (Epshtein, 1911); U.S.A. (Kudo, 1922; Sprague, 1940); Yugoslavia (Ivanić, 1926). _Blattella germanica_, U.S.A. (Crawley, 1905); Germany (Wellmer, 1910, 1911). _Periplaneta americana_, Brazil (Lutz and Splendore, 1903). This organism (fig. 2, B) passes its life cycle living free in the lumina of the malpighian tubules of cockroaches. The elongate trophozoite is firmly attached to the wall of the tubule as are clusters of immature spores. Mature spores are freed into the lumina of the tubules from whence they pass to the exterior. Sprague (1940) examined about 200 wild-caught _B. orientalis_ and found them to be practically 100 percent infected. Order MICROSPORIDIA Family NOSEMATIDAE =Plistophora kudoi= Sprague and Ramsey _Natural host._--_Blatta orientalis_, U.S.A., Illinois, West Virginia, Kentucky (Sprague and Ramsey, 1941, 1942): Found in the epithelial cells of caeca and midgut. Considerable damage is done to these cells. Seventy-five percent of 52 _B. orientalis_ harbored the parasite. =Plistophora periplanetae= (Lutz and Splendore)