Phylum ASCHELMINTHES Class NEMATODA Order OXYUROIDEA Family OXYURIDAE * =Enterobius vermicularis= (Linnaeus, 1758) Leach in Baird, 1853 _Natural vectors._--_Blatta orientalis_ and _Blattella germanica_, U.S.S.R. (Sondak, 1935). Order ASCAROIDEA Family ASCARIDAE * =Ascaris lumbricoides= Linnaeus, 1758 _Natural vector._--_Periplaneta americana_, South Africa (Porter, 1930): The eggs may have been those of _A. suum_ Goeze, 1782. _Experimental vectors._--_Periplaneta americana_, Gold Coast Colony (Macfie, 1922); India (Chandler, 1926). _Periplaneta americana_, _Periplaneta australasiae_, _Neostylopyga rhombifolia_, Formosa (Morischita and Tsuchimochi, 1926). * =Ascaris= sp. _Natural vector._--_Blatta orientalis_, Italian Somaliland (Mariani and Besta, 1936). _Experimental vector._--_Periplaneta americana_, Uruguay (Pérez Fontana, 1955): Eggs recovered from the insects' feces. Order STRONGYLOIDEA Family ANCYLOSTOMIDAE * =Ancylostoma caninum= (Ercolani, 1859) Hall, 1913 _Experimental vector._--_Periplaneta americana_, Netherlands (Akkerman, 1933). * =Ancylostoma ceylanicum= (Looss, 1911) Leiper, 1915 _Experimental vector._--_Periplaneta americana_, Gold Coast Colony (Macfie, 1922); Netherlands (Akkerman, 1933). * =Ancylostoma duodenale= (Dubini, 1843) Creplin, 1845 _Natural vector._--_Periplaneta americana_, South Africa (Porter, 1929, 1930). _Experimental vector._--_Periplaneta americana_, Gold Coast Colony (Macfie, 1922). * =Necator americanus= (Stiles, 1902) Stiles, 1906 _Natural vector._--_Periplaneta americana_, India (Chandler, 1926). _Experimental vector._--_Periplaneta americana_, Gold Coast Colony (Macfie, 1922). * =Hookworm ova= _Experimental vectors._--_Periplaneta americana_, _Periplaneta australasiae_, _Neostylopyga rhombifolia_, Formosa (Morischita and Tsuchimochi, 1926). Family TRICHOSTRONGYLIDAE * =Trichostrongylus= sp. _Natural vector._--_Blatta orientalis_, Italian Somaliland (Mariani and Besta, 1936). Order TRICHUROIDEA Family TRICHURIDAE * =Capillaria hepatica= (Bancroft, 1893) Travassos, 1915 _Experimental vector._--_Blatta orientalis_, Italy? (Giordano, 1950). * =Trichuris trichiura= (Linnaeus, 1771) Stiles, 1901 _Natural vectors._--_Blatta orientalis_, Italian Somaliland (Mariani and Besta, 1936); U.S.S.R. (Sondak, 1935). _Blattella germanica_, U.S.S.R. (Sondak, 1935). _Periplaneta americana_, Gold Coast Colony (Macfie, 1922); Formosa (Morischita and Tsuchimochi, 1926). _Experimental vectors._--_Periplaneta americana_, Gold Coast Colony (Macfie, 1922); India (Chandler, 1926); Uruguay (Pérez Fontana, 1955). _Periplaneta americana_, _Periplaneta australasiae_, and _Neostylopyga rhombifolia_, Formosa (Morischita and Tsuchimochi, 1926). XII. ARTHROPODA