Rehn and Hebard (1914) stated of _Supella supellectilium_ in Florida that "The females were all taken in cupboards where _Blattella germanica_ was found in swarms." The association in human habitations of _S. supellectilium_ and _B. germanica_ has been reported also by Sein (1923), Puerto Rico; Shaw (1924), Australia; Mallis (1954): "German and brown-banded roaches were often found in the same crevice."; Anonymous (1958), Texas; and Anonymous (1958a), Georgia. Gould and Deay (1940) stated that other species of cockroaches, especially _B. germanica_, may be found with _S. supellectilium_ in the same part of a building. Yet Shaw (1925) stated that "when _Supella supellectilium_ Serv. invades places already occupied by _Blattella germanica_ L., it tends to oust the latter." _Blaberus discoidalis_ has been found in homes or in fruit debris in Puerto Rico in company with the more common, domiciliary species _Leucophaea maderae_, but never in abundance (Sein, 1923; Wolcott, 1950). Illingworth (1915) in Hawaii found _Symploce hospes_ associated with _Nauphoeta cinerea_, _Graptoblatta notulata_, and _Diploptera punctata_. Hebard (1917) found _Aglaopteryx diaphana_ in a bromeliad on a forest tree in Jamaica together with _Nyctibora laevigata_ and numerous _Cariblatta insularis_. He also found numerous _Aglaopteryx gemma_ under signs on longleaf pines in Alabama with occasional specimens of _Parcoblatta lata_. In Virginia he found _Parcoblatta uhleriana_ in a decaying chestnut log with _Cryptocercus punctulalus_. In Florida he found _Latiblattella rehni_ with _Eurycotis floridana_ and, more rarely, with _Periplaneta australasiae_ under bark of pine trees. In Key West he found _Symploce hospes_ in the cupboard of a hotel with swarms of _Blattella germanica_ and a few _Supella supellectilium_. Rehn and Hebard (1927) in their study of West Indian blattids reported finding _Neoblattella proserpina_ in epiphytic bromeliads in Jamaica in company with _Neoblattella eurydice_ and _Neoblattella dryas_. They also list most of the associations cited by Hebard (1917). Ramme (1923) reported that he found in Germany four species of _Ectobius_ (_lapponicus_, _lucidus_, _pallidus_, and _sylvester_) living together in an area about 50 m. by 200 m. Although he had stated that his specimens of _E. lucidus_ were a distinct species in 1923, Ramme (1951) later decided that they were a form of _E. sylvester_, _E. sylvester_ f. _lucidus_. Dow (1955) reported trapping _Blattella germanica_, _Periplaneta americana_, and _Periplaneta brunnea_ in houses and privies in south Texas. At our request Dr. Dow (personal communication, 1958) analyzed his records to determine whether there were indications of associations between these species, with the following results: