_Experimental infection._--_Blatta orientalis_, Europe (Filatoff, 1904): The organism was not pathogenic when fed to the cockroach, but killed the insects when injected into the body cavity; after the insects died Filatoff reisolated this pathogen together with another bacillus from the cadavers. He succeeded in culturing the new microorganism and found it to be pathogenic when injected into, but not when fed to, the cockroaches. The diseased insects became sluggish, failed to eat or drink, turned over on their backs, their extremities became totally paralyzed, and they finally died. =Bacillus megaterium= De Bary _Habitat._--Soil, water, decomposing materials. _Natural vectors._--_Periplaneta americana?_ ("_Blatella americana_"), England (Shrewsbury and Barson, 1948): From intestinal tract. _Experimental vectors._--_Blatta orientalis_, Italy (Cao, 1898): Organism recovered, apparently unchanged, from intestinal contents. [cross] =Bacillus monachae= (von Tubeuf) Eckstein _Synonymy._--_Bacterium monache._ _Source._--Diseased larvae of nun moth, _Lymantria monacha_. _Experimental infection._--_Blatta orientalis_, Europe (Filatoff, 1904): Organism pathogenic to the cockroach when injected but not when fed. [cross] =Bacillus periplanetae= Tichomiroff _Habitat._--_Blatta orientalis_, U.S.S.R.? (Tichomiroff, 1870[?], _in_ Filatoff, 1904): The infected insects suffered from a diarrhea and the liquid feces were yellow-brown. [cross] =Bacillus stellatus= Hollande _Natural infection._--_Blatta orientalis_, France (Hollande, 1934): Organism observed regularly in the intestine (especially rectum). Extensive description given. [cross] =Bacillus radiciformis= _Experimental vectors._--_Blatta orientalis_, Italy (Cao 1898): Organism recovered, apparently unchanged, from intestinal contents. * =Bacillus subtilis= Cohn emend. Prazmowski _Natural vectors._--_Blaberus craniifer_, U.S.A. (Wedberg et al., 1949). _Blatta orientalis_, Italy (Cao, 1898, 1906; Spinelli and Reitano, 1932); France (Sartory and Clerc, 1908); Poland (Nicewicz et al., 1946). _Cryptocercus punctulatus_, U.S.A. (Hatcher, 1939). _Periplaneta americana?_ ("_Blatella americana_"), England (Shrewsbury and Barson, 1948). Cockroaches, U.S.A. (Longfellow, 1913). _Experimental vectors._--_Blatta orientalis_, Italy (Cao, 1898, 1906). "=Bacillus subtilis= group" _Natural infection._--_Blatta orientalis_, Italy (Ronzoni, 1949): Isolated from oöthecae. [cross] =Bacillus tritus= Batchelor _Habitat._--Isolated from feces (man?). _Natural vectors._--_Blatta orientalis_, Poland (Nicewicz et al., 1946): Isolated from intestinal tract. * =Clostridium feseri= Trevisan _Experimental vectors._--_Blatta orientalis_, Italy (Cao, 1898). =Clostridium lentoputrescens= Hartsell and Rettger _Habitat._--Soil, intestinal tract of man. _Natural vectors._--_Blatta orientalis_, Poland (Nicewicz et al., 1946): Isolated from intestinal tract.