_Natural hosts._--_Blatta orientalis_, Germany (Siebold, 1837, 1839; Stein, 1848; Bütschli, 1881; Wolters, 1891; Marshall, 1892; Wellmer, 1910, 1911; Foerster, 1938; Schubotz, 1905); U.S.A. (Leidy, 1853a; Crawley, 1903; Watson, 1917; Kudo, 1922; McAdow, 1931; Sprague, 1940, 1941); England (Lankester, 1863); France (Schneider, 1875; Cuénot, 1901; Laveran and Franchini, 1920a); Brazil (Magalhães, 1900; Pinto, 1919); U.S.S.R. (Zasukhin, 1929, 1930). _Blattella germanica_, U.S.A. (Crawley, 1903); South Africa (Fantham, 1929; Porter, 1930: these appear to be the same record). _Blattella germanica_ and/or _Periplaneta americana_, Egypt (DeCoursey and Otto, 1956, 1957). _Periplaneta americana_, Brazil (Magalhães, 1900); U.S.A. (Crawley, 1903; 1907; McAdow, 1931); South Africa (Fantham, 1929; Porter, 1930: these appear to be the same record); Gold Coast Colony (Macfie, 1922). _Parcoblatta pensylvanica_, U.S.A., Michigan (Ellis, 1913a). Cockroaches, Germany (Schiffmann, 1919: probably used the oriental cockroach); Venezuela (Tejera, 1926). Organism usually found in the intestinal tract of cockroaches where it is attached to the gut cells. Cysts are passed in the feces. Occasionally, _G. blattarum_ (fig. 2, J) is found in the body cavity (Leidy, 1853a; Hall, 1907). Though this is considered to be one of the commonest of the Sporozoa encountered in cockroaches, DeCoursey and Otto (1956) found only 10 of 217 _P. americana_ and _B. germanica_, collected in restaurants in Egypt, infested with this species. Watson (1917) found a dozen or more in one specimen of _Blatta orientalis_. Zasukhin (1929, 1930) found 2.6 percent of 3,000 oriental cockroaches infected with this parasite. =Gregarina fastidiosa= Harrison _Natural host._--_Aptera fusca_, South Africa (Harrison, 1955): All mature females were heavily infected; in all specimens there were over 100 parasites in the gut. All nymphs were infected, the earlier instars more lightly than the later instars. Gregarines were found in all parts of the gut except the crop and gizzard. =Gregarina gibbsi= Harrison _Natural host._--_Temnopteryx phalerata_, South Africa (Harrison, 1955): Although the cockroaches were found in groups, only 32 percent were infected and only 10 percent heavily. The gregarines were found in the anterior mesenteron but none in the hepatic caeca. All cysts were found in the hind gut or rectum. =Gregarina illinensis= M. E. Watson _Natural host._--_Parcoblatta pensylvanica_, U.S.A., Illinois (Watson, 1915, 1916): The intestine of one cockroach was found to contain 25 of these gregarines. =Gregarina impetuosa= Harrison _Natural host._--_Melanosilpha capensis_, South Africa (Harrison, 1955): All specimens of this gregarine were found in the anterior mesenteron of the host. =Gregarina légeri= Pinto _Natural host._--_Periplaneta americana_, Brazil (Pinto, 1918, 1918a, 1919): Intestinal canal. =Gregarina neo-brasiliensis= Al. Cunha