338 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I4I 



feral species. As might be expected, most of the following examples 

 pertain to domiciliary cockroaches. 



Dozier (1920) occasionally found Periplaneta americana with 

 Eurycotis floridana in decaying stumps, beneath loose bark of de- 

 cayed trees, and beneath corded wood. Adair (1923) stated that in 

 his house in Egypt Periplaneta americana, Blatta orientalis, and Blat- 

 tella germanica were found together in a cupboard. Sambon (1925) 

 found B. orientalis and B. germanica side by side but not fraternizing 

 in a home in Italy. Gould and Deay (1938) observed that apartments 

 over stores were infested with both B. germanica and P. americana, 

 but did not indicate whether these occupied the same microhabitat. 

 Gould and Deay (1940) observed that in the Purdue University 

 greenhouse Periplaneta fuUginosa was found "under benches, boxes, 

 pots and other objects in association with the American roach." Dr. 

 L. A. Hetrick (personal communication, 1954) wrote us that several 

 summers before he had had a mixed infestation of cockroaches, which 

 included Periplaneta australasiae, Periplaneta fuUginosa, and Pycno- 

 scelus surinamensis, in his chicken shed. 



Eads (personal communication, 1955), in response to our inquiry 

 about the mixed populations of cockroaches that he had reported in- 

 festing sewers in Texas (Eads et al., 1954), stated that "Each of the 

 ten colonies oi B. orientalis found in Tyler manholes were associated 

 with larger colonies of F. americana. True breeding colonies oi B. 

 orientalis appeared to be present since all the developmental stages 

 were taken. The same situation existed with the P. fuUginosa and the 

 two species of Parcoblatta. Larger colonies of P. americana were 

 associated with the other species in each case. From our limited ob- 

 servations the two species always appeared to be perfectly compati- 

 ble." Eads et al. (1954) had found Periplaneta fuUginosa in three 

 manholes, Parcoblatta holliana in one manhole and Parcoblatta pensyl- 

 vanica in one manhole. We assume that the groups of each species 

 were spacially discrete so that they were recognizable as colonies. 

 Dr. T. A. Olson (personal communication, 1958) has observed two or 

 more species of cockroaches in a single structure but never in mixed 

 colonies. Each species was separated physically from the others. Olson 

 concluded that cockroaches of different species do not mingle freely 

 unless forced to do so by some special environmental condition. Pettit 

 (1940) found B. germanica and P. americana similarly separated in 

 the same building or even in the same basement laboratory. 



Perkins (1899) found Lobopterella dimidiatipes generally living in 

 company with the young of Periplaneta australasiae in Hawaii. Rehn 

 and Hebard (1914) in Florida found P. australasiae abundant with 



