Oöthecae of _Periplaneta americana_, U.S.A., Pennsylvania (Roth and Willis, unpublished data, 1952): Inside oöthecae. Determination by Miss Mary Downing. * =Aspergillus fumigatus= Fresenius _Natural vector._--_Blatta orientalis_, France (Sartory and Clerc, 1908): From intestine. * =Aspergillus niger= van Tieghem _Natural vector._--_Periplaneta americana_, U.S.A., Texas (McShan in Roth and Willis, 1957a): From feces. _Experimental vector._--_Blatta orientalis_, Italy (Cao, 1898): Organism passed unchanged through the gut of the insects. =Aspergillus sydowi= (Bainier and Sartory) Thom and Church _Natural host._--Oötheca of _Eurycotis floridana_, U.S.A., Pennsylvania (Roth and Willis, unpublished data, 1952): On outer surface. Determination by Miss Mary Downing. =Aspergillus tamarii= Kita _Natural host_.--Oöthecae of _Blattella germanica_, U.S.A., Pennsylvania (Roth and Willis, unpublished data, 1952): On exterior surface. Determination by Miss Mary Downing. =Aspergillus= sp.? _Natural and experimental vector._--_Blattella germanica_, on shipboard (Morrell, 1911): Isolated from feces. Experimentally Morrell also showed that the spores of the fungus could be recovered from feces of cockroaches that had fed on them. =Aspergillus= sp. _Natural vector._--_Periplaneta americana_, England (Bunting, 1956): The fungus was isolated mostly from imperfectly excreted feces. =Beauveria bassiana= (Balsamo) Vuillemin _Experimental host._--_Blattella germanica_ and _Periplaneta americana_, U.S.A. (Dresner, 1949, 1950): The nymphs of American cockroaches became infected when they (1) were injected with a 1-percent suspension of spores, (2) ate rat pellets sprayed with the spore suspension, or (3) were dusted with the fungus spores. The symptoms of the fungus infection were paralysis followed by death; some of the infected insects liquefied, others dried up after the appearance of a subcuticular blackening. =Cephalosporium= sp. _Natural vector._--_Periplaneta americana_, U.S.A., Texas (McShan, unpublished MS., 1953): From feces of cockroaches collected in the basement of a grain elevator at the docks in Galveston. * =Geotrichum candidum= Link _Experimental vector._--_Blatta orientalis_, Italy (Cao, 1898): Organism retained its pathogenicity after passing through the insect's gut. =Penicillium= sp. _Natural vector._--_Blaberus craniifer_, U.S.A. (Wedberg et al., 1949): From feces. _Periplaneta americana_, England (Bunting, 1956): Mostly from imperfectly excreted feces. =Metarrhizium anisopliae= (Metschnikoff) Sorokin _Natural hosts._--_Blattidae_, Seymour (1929); Charles (1941). _Panesthia australis_, U.S.A., Massachusetts (Roth and Willis, unpublished data, 1957): Growing on adult specimens that were found dead in a laboratory colony. Determination by Miss Dorothy Fennell. _Periplaneta americana_, England (Bunting, 1956): Growing on genitalia of females where it prevented oöthecal formation.