Cockroach, Puerto Rico (Johnston, 1915): From a "small roach" in the pathological collection at Rio Piedras (no data). Family DEMATIACEAE =Memnoniella echinata= (Rivolta) Galloway _Natural host._--Oötheca of _Blattella germanica_, U.S.A., Pennsylvania (Roth and Willis, unpublished data, 1952): On material that had oozed from a damaged oötheca. Determination by Miss Mary Downing. =Torula acidophila= Owen and Mobley _Natural host._--_Periplaneta americana_, U.S.A. (Owen and Mobley, 1948): The digestive tract of this cockroach is the normal habitat of this yeast which was transmitted to sirup by the insects. The yeast superimposed a foreign taste, suggestive of malic acid, upon the original flavor of the sirup. =Torula gropengiesseri= Lodder _Natural host._--_Blatta orientalis_, Germany (Gropengiesser, 1925; Lodder, 1934): Isolated from fat body and oöthecae. Gier (1947) is of the opinion that the so-called yeasts that supposedly may displace the bacteroids in the fat body (Mercier, 1907b; Gropengiesser, 1925) may actually represent poorly fixed and insufficiently stained bacteroids. =Torula rosea= Preuss _Experimental host._--_Blaberus craniifer_, U.S.A. (Wedberg et al., 1949): Upon repeated feeding of massive doses of this yeast to the cockroach, these workers were able to isolate the organism from the feces up to six days thereafter. There was no evidence that _T. rosea_ was pathogenic for _B. craniifer_. Class PHYCOMYCETES Order MUCORALES Family MUCORACEAE =Mucor guilliermondii= Nadson and Filippov _Natural host._--_Periplaneta americana_, U.S.S.R. (Nadson and Filippov, 1925; Filippov, 1926): Isolated and cultured from intestine. =Mucor= sp. _Natural host._--Oötheca of _Periplaneta americana_, U.S.A., Pennsylvania (Roth and Willis, unpublished data, 1952): Inside oötheca. Determination by Miss Mary Downing. _Pycnoscelus surinamensis_, Germany (Bode, 1936): Isolated from fat body which it had stained red. =Rhizopus nigricans= Ehrenberg _Natural vector._--_Blaberus craniifer_, U.S.A. (Wedberg et al., 1949): From feces. =Rhizopus= sp. _Natural vector._--_Periplaneta americana_, U.S.A., Texas (McShan, unpublished MS., 1953): From feces. =Syncephalastrum= sp. _Natural vector._--_Periplaneta americana_, U.S.A., Texas (McShan, unpublished MS., 1953): From feces. Order ENTOMOPHTHORALES Family BLASTOCYSTIDACEAE =Blastocystis hominis= Brumpt _Natural vector._--_Blatta orientalis_, U.S.S.R. (Zasukhin, 1930): In hind gut in 40 percent of over 3,000 cockroaches. =Blastocystis= sp. _Natural vectors._--_Blatta orientalis_, U.S.S.R. (Yakimov and Miller, 1922): Found in the intestinal contents of 29 percent of 124 _B. orientalis_. Cockroaches, Venezuela (Tejera, 1926). * * * * * The placement of the following fungus is problematic. =Coccidioides periplanetae= Avrech