_Natural host._--_Blattella germanica_, U.S.A. (Keegan, 1944): Three mites found on 238 cockroaches examined; others taken in debris from floor of cockroach cage (Keegan, 1944). Members of this family are predaceous (Baker and Wharton, 1952). Family LAELAPTIDAE =Blattilaelaps nauphoetae= Womersley _Natural host._--_Nauphoeta cinerea_, Australia, Brisbane (Womersley, 1956). =Coleolaelaps= (?) sp. _Natural host._--_Gromphadorhina portentosa_, the hosts were imported into U.S.A. from Madagascar via Europe (Roth and Willis, unpublished data, 1958): The mites (pl. 12, C) were tentatively determined by Dr. E. W. Baker. =Hypoaspis= sp. _Natural host._--_Panesthia australis_, imported into U.S.A. from Australia (Roth and Willis, unpublished data, 1955): Cockroach determined by J. A. G. Rehn. Generic determination of mite made by Dr. R. W. Strandtmann (Camin, personal communication, 1955). Family UROPODIDAE =Uropoda= sp. _Natural host._--_Blattella humbertiana_, Formosa (Takahashi, 1940). Nymphs of the cockroach may be destroyed (Takahashi, 1940). Uropodids frequently attach themselves to insects, especially in nymphal stages but probably are harmless (Baker and Wharton, 1952). Family DIPLOGYNIIDAE =Undetermined diplogyniid= _Natural host._--_Panesthia australis_, imported into U.S.A. from Australia (Roth and Willis, unpublished data, 1955): Cockroach determined by J. A. G. Rehn. According to Dr. J. H. Camin (personal communication, 1955) this is a new genus and new species in the subfamily Diplogyniinae, and is most closely related to the genus _Lobogynioides_. Mites of this family live as ectoparasites and commensals on beetles and possibly other insects (Baker and Wharton, 1952). Family ANOETIDAE =Histiostoma feroniarum= (Dufour) _Natural host._--_Pycnoscelus surinamensis_, Germany (Roeser, 1940): Though not parasitic, the mites at times became so numerous that the insects were hindered in their movement, were unable to feed, and died. The mites were introduced with soil and leaves and had originally been attached to millipedes, waterfleas, and sowbugs. The deutonymphs, hypopial forms, or travelers are found on insects; the other stages are found in decaying organic matter (Baker and Wharton, 1952). Family ACARIDAE =Caloglyphus spinitarsus= (Hermann) _Natural host._--_Pycnoscelus surinamensis_, Germany (Roeser, 1940): See notes following _Histiostoma feroniarum_ above. =Caloglyphus= sp. _Natural hosts._--_Blattella germanica_ and _Periplaneta americana_, U.S.A. (Piquett and Fales, 1952): Mite feeds on organic matter but can reduce the vigor of a cockroach colony. =Tyrophagus lintneri= (Osborne) _Common name._--Mushroom mite.