342 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I4I 



nymphs oi B. geTmanica with fourth- and fifth-instar nymphs of B. 

 orientalis, which are all practically of equal size, sometimes he would 

 find mixed groups, but generally the groups were distinct. Lucas 

 (1912) stated that Burr had found B. germanica and B. orientalis 

 swarming within a rubbish heap in England ; presumably both colonies 

 were breeding and multiplying and one species was not detrimental to 

 the presence of the other. 



Shaw (1925) claimed that Supella supellectilium tended to oust 

 Blattella germanica, but Pope (1953) thought it doubtful in Queens- 

 land. Wolcott (1950) stated that "The larger and more powerful 

 domestic cockroaches, Periplaneta americana (L.), P. aiistralasiae 

 (F.) and P. hrimnea Burmeister have very definitely fallen be- 

 hind in Puerto Rico in competition with the little German roach." 

 Pessoa and Corea (1928) observed that other species of cockroaches 

 were rare in Brazil in houses that were infested with Leucophaea 

 maderae. Lederer (1952) noticed that in the reptile house of the 

 aquarium at Frankfort am Main Blatta orientalis was obviously kept 

 down by Blattella germanica, even before the appearance of P. ameri- 

 cana. However, B. germanica was not driven out of the reptile house 

 by P. americana although the populations of each fluctuated for about 

 22 years after the American cockroach had settled there ; both species 

 occupied separate resting places. Lederer further observed that within 

 four years of the introduction of P. americana into the crocodile 

 house, none of the original infestation of B. orientalis could be found ; 

 a small colony of Pycnoscelus surinamensis in the reptile house was 

 apparently also driven out by P. americana. Chopard (1932, 1938) 

 stated that the oriental cockroach does not exist in company with P. 

 americana which very probably destroys it. Pettit (1940) kept B. 

 germanica and P. americana together in a cage for several weeks but 

 neither species gave any indication of feeding on the other. 



Froggatt (1906) stated that "It is probable that the advent of the 

 larger and more formidable American cockroach into Australia has 

 led to the retirement or destruction of our indigenous species" [pre- 

 sumably Periplaneta australasiae]. Tillyard (1926) noted that this 

 statement is incorrect as neither species is native to Australia. Yet 

 Shaw (1925) stated that in Australia "When both species live together 

 in the same places, australasiae Fabr. will probably be found gradually 

 to displace americana L." Local fluctuations in the relative abundance 

 of these species could be a basis for such dissimilar observations. 

 However, MacDougall (1925) observed that in the plant houses of 

 the Royal Botanical Garden, Edinburgh, the Australian cockroach 



