Paramecium sp.
Natural associate.—Cockroaches, U.S.A., Maryland (Cleveland, 1927): Three of 30 cockroaches collected in the basement of a department 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