_Experimental vectors._--_Blatta orientalis_, Europe (Filatoff, 1904): Organism pathogenic to cockroach when injected but not when fed. =Escherichia coli= var. =communior= (Topley and Wilson) Yale _Natural vectors._--_Blaberus craniifer_, U.S.A. (Wedberg et al., 1949): From feces. =Escherichia freundii= (Braak) Yale _Habitat._--Soil, water, intestinal canal of man and other animals. _Natural vectors._--_Blaberus craniifer_, U.S.A. (Wedberg et al., 1949): From feces. _Blattella germanica_, U.S.A. (Janssen and Wedberg, 1952): From intestinal canal and feces. _Periplaneta americana_, U.S.A. (Bitter and Williams, 1949): From intestinal tract. =Escherichia intermedium= (Werkman and Gillen) Vaughn and Levine _Habitat._--Soil, water, intestinal canal of man and other animals. _Natural vectors._--_Periplaneta americana_, U.S.A. (Bitter and Williams, 1949): From intestinal canal. * =Klebsiella pneumoniae= (Schroeter) Trevisan _Experimental vectors._--_Blatta orientalis_, Italy (Cao, 1898). * =Paracolobactrum aerogenoides= Borman, Stuart and Wheeler _Natural vectors._--_Blattella germanica_, U.S.A. (Janssen and Wedberg, 1952). _Periplaneta americana_, U.S.A. (Bitter and Williams, 1949). * =Paracolobactrum coliforme= Borman, Stuart and Wheeler _Natural vectors._--_Blattella germanica_, U.S.A. (Janssen and Wedberg, 1952). _Periplaneta americana_, U.S.A. (Bitter and Williams, 1949). * =Paracolobactrum= spp. _Natural vectors._--_Blatta orientalis_, U.S.A. (Olson and Rueger, 1950). _Blattella germanica_, U.S.A. (Olson and Rueger, 1950). _Periplaneta americana_, U.S.A. (Bitter and Williams, 1949; Olson and Rueger, 1950). * =Paracolon bacilli= _Natural vectors._--Cockroaches [presumably _Blatta orientalis_, _Blattella germanica_ and/or _Periplaneta americana_], Egypt (El-Kholy and Gohar, 1945). * =Proteus mirabilis= Hauser _Natural vectors._--_Periplaneta americana_, U.S.A. (Bitter and Williams, 1949, 1949a). * =Proteus morganii= (Winslow et al.) Rauss _Natural vectors._--_Periplaneta americana_, U.S.A. (Bitter and Williams, 1949, 1949a). Cockroaches [presumably _Blatta orientalis_, _Blattella germanica_, and/or _Periplaneta americana_], Egypt (El-Kholy and Gohar, 1945). * =Proteus rettgeri= (Hadley et al.) Rustigian and Stuart _Natural vectors._--_Periplaneta americana_, U.S.A. (Bitter and Williams, 1949). * =Proteus vulgaris= Hauser _Natural vectors._--_Blaberus craniifer_, U.S.A. (Wedberg et al., 1949). _Blatta orientalis_, Italy (Spinelli and Reitano, 1932). _Periplaneta americana_, U.S.A. (Bitter and Williams, 1949, 1949a). Cockroaches, U.S.A. (Longfellow, 1913). * =Proteus= spp. _Natural vectors._--_Blatta orientalis_, U.S.A. (Olson and Rueger, 1950). _Periplaneta americana_, U.S.A. (Bitter and Williams, 1949; Olson and Rueger, 1950). * =Salmonella anatis= (Rettger and Scoville) Bergey et al. _Natural vectors._--_Periplaneta americana_, U.S.A. (Eads et al., 1954).