_Associate._--_Pycnoscelus surinamensis_, U.S.A. (Roth and Willis, unpublished data, 1953): Mite determined by Dr. E. W. Baker (personal communication, 1953). Although this mite was found on the cockroach, it is a known pest in stored foods (Baker and Wharton, 1952) and probably was brought into the culture with food. Rau (1924) reported that the food of _Blatta orientalis_ often became infested with this species, but it did not affect the health or mortality of the cockroaches in his culture. =Tyrophagus noxius= A. Z. _Natural host._--_Periplaneta americana_, U.S.A. (Roth and Willis, unpublished data, 1953): Mite determined by Dr. E. W. Baker (personal communication, 1953). Mites were found in the oöthecal cavity of a female cockroach that had been isolated for her entire adult life. The mites were in a closely packed mass behind a plug of what appeared to be feces, disintegrated eggs, and dried blood; none of the mites were visible until this plug was removed. Baker (personal communication, 1953) stated that the mite is probably not parasitic and that species of the genus feed on organic matter. =Rhizoglyphus tarsalus= Banks _Natural host._--_Periplaneta americana_, U.S.A. (Rau, 1940a): Not normally parasitic on cockroaches, but the mites became so numerous at times they would attack living as well as dead and dying cockroaches. Family GLYCIPHAGIDAE =Chaetodactylus= sp. _Synonymy._--_Trichotarsus_ sp. [Baker and Wharton, 1952]. _Natural host._--_Leucophaea maderae_, Puerto Rico (Seín, 1923): Mites found on cockroach's thorax and particularly among the folds of the wings (Seín, 1923). Mites of this genus are found infesting organic matter (Baker and Wharton, 1952). Family PODAPOLIPODIDAE =Locustacarus= sp. _Natural hosts._--_Diploptera punctata_ and _Nauphoeta cinerea_, U.S.A. (Roth and Willis, unpublished data, 1954): Mite genus determined by Dr. E. W. Baker (personal communication, 1954). The mites cluster thickly on intersegmental membranes, particularly around the coxae and neck. Despite a heavy infestation, the colony of _Nauphoeta_ thrived for several years. This mite was found first on _N. cinerea_ and possibly transferred to _D. punctata_ when the latter was brought into the laboratory from Hawaii. Family IOLINIDAE =Iolina nana= Pritchard _Natural hosts._--_Blaberus craniifer_ (originally from a culture at Harvard University) and _Diploptera punctata_ (originally from Hawaii), U.S.A., Pennsylvania (Roth and Willis, unpublished data, 1953; Pritchard, 1956): The mites usually attached near the wing bases of the insects. Morphologically, the species is intermediate between certain predaceous and phytophagous mites (Pritchard, 1956). Family PTERYGOSOMIDAE =Pimeliaphilus podapolipophagus= Trägårdh _Common name._--Cockroach mite. _Natural hosts._--_Parcoblatta_ sp., U.S.A. (Edmunds, 1953a). _Periplaneta americana_, U.S.A. (Piquett and Fales, 1952). Cockroaches. U.S.A. (Baker and Wharton, 1952).