BIOTIC ASSOCIATIONS OF COCKROACHES — ROTH & WILLIS 187 



partment store had paramecia in their stomachs but none in the 

 rectum. 



Experimental associate. — Periplaneta americana, U.S.A. (Hegner, 

 1929) : Paramecia fed to the cockroaches were recovered from the 

 crop at intervals from one-half to six and one-half hours. In no case 

 were the protozoa recovered from the stomach alive. 



Cockroaches, U.S.A., Maryland (Cleveland, 1927). About 200 

 starved cockroaches were fed a culture of Paramecium. Few, if any, 

 of the protozoa were killed in the stomach during the first two hours, 

 but all were killed within 5 to 6 hours after ingestion. 



Family ISOTRICHIDAE 



Isotricha caulleryi Weill 



Natural host. — Periplaneta americana, Indochina (Weill, 1929) : 

 Alimentary canal. 



Order SPIROTRICHA 



Family BURSARIIDAE 



Balantidium blattarum Ghosh 



Natural host. — Periplaneta americana, India (Ghosh, 1922; 

 Bhatia and Gulati, 1927) ; Gold Coast Colony (Macfie, 1922) : In- 

 testinal tract. 



♦Balantidium coli (Malmsten) 



Experimental vector. — Cockroach, Venezuela (Tejera, 1926). 



Balantidium ovatum Ghosh 



Natural host. — Periplaneta americana, India (Ghosh, 1922a ; Bhatia 

 and Gulati, 1927) ; Indochina, Saigon (Weill, 1929) : Intestinal tract. 



Balantidium praenucleatum Kudo and Meglitsch 



Natural host. — Blatta orientalis, U.S.A., Illinois (Kudo and Meg- 

 litsch, 1938 ; Meglitsch, 1940) : This protozoan is found in the lumen 

 of the anterior region of the colon in association with several other 

 species of protozoa. Only y.6 percent of 500 cockroaches examined 

 contained B. praenucleatum. The largest number encountered in a 

 single host was 59, but as a rule each host harbored a smaller number. 



Balantidium sp. ? 



Natural host. — Periplaneta americana, Brazil (Magalhaes, 1900) : 

 These organisms were numerous in the intestine. 



