_Periplaneta americana_, Germany (Bode, 1936): Attacked by "_Mermis_" or "_Gordius_." It has been suggested that the name _Mermis_ is often applied without critical identification to immature Nematoda found in insects (Buxton, 1955). Order RHABDITOIDEA Family DIPLOGASTERIDAE =Diplogaster= sp. _Synonymy._--_Lycolaimus_ [Goodey, 1951]. _Experimental Host._--_Blattella germanica_, U.S.A. (Christie and Crossman, 1933). Family STEINERNEMATIDAE =Neoaplectana= sp. _Experimental hosts._--_Blattella germanica_, _Nauphoeta cinerea_, and _Periplaneta americana_. U.S.A. (Dutky and Hough, 1955): This nematode, found in codling moth larvae, is close to _Neoaplectana chresima_ Steiner but apparently is a new species. _Nauphoeta cinerea_ was very susceptible to infection; _B. germanica_ and _P. americana_ were less susceptible. Order OXYUROIDEA Family THELASTOMATIDAE These nematodes are found in the intestinal tract of cockroaches. =Aorurus philippinensis= Chitwood and Chitwood, 1934 _Natural host._--_Panesthia angustipennis_, Philippine Islands (Chitwood and Chitwood, 1934). =Binema mirzaia= (Basir, 1940) Basir, 1956 _Synonymy._--_Periplaneticola mirzaia_ Basir, 1940. _Natural host._--_Periplaneta americana_, India, Aligarh (Basir, 1940). =Blattelicola blattelicola= Basir, 1940 _Natural host._--_Blattella germanica_, India, Aligarh (Basir, 1940). =Blatticola blattae= (Graeffe, 1860) Chitwood, 1932 _Synonymy._--_Oxyuris blattae_ Graeffe, 1860; _Oxyuris blatticola_ Galeb, 1878; _Blatticola blatticola_ (Galeb, 1877) Schwenck, 1926 [Chitwood, 1930, 1932]. _Natural hosts._--_Blattella germanica_, Brazil (Pessôa and Corrêa, 1926; Schwenck, 1926); U.S.A. (Chitwood, 1930; Bozeman, 1942); Egypt? (Galeb, 1877, 1878); U.S.S.R. (Sobolev, 1937; Sondak, 1935); Czechoslovakia (Groschaft, 1956). _Ectobius lapponicus_, _Ectobius pallidus_, Egypt? (Galeb, 1877, 1878). _Polyphaga aegyptiaca_, France (Graeffe, 1860). The life cycle has been studied by Bozeman (1942): He found never more than four worms in the large intestine of each cockroach. Embryos developed to "resting" stage in vitro. The resting stage was infective while the active stage was not. The worms seemed to have no effect on the vital activities of the host. Alicata (1934b) found that the embryo undergoes a molt before hatching. Chitwood (1930) found 75 percent of the German cockroaches examined from houses in Washington infected. As a rule, one adult female, one or two males, and possibly two larval females are found in a single individual, apparently only in the rectum.