ITS NATURAL HISTORY. 19 



The other species of Cockroaches which have been met with 

 in Europe are Pane/flora maderce, said by Stephens to be occa- 

 sionally seen in London, and Blabera gigantea, the Drummer of 

 the TVest Indies, which has often been found alive in ships in 

 the London Docks. 



Blatta germanica, Periplaneta orientalis, and P. americana, are 

 so similar in habits and mode of life as to be interchangeable, 

 and each is known to maintain itself in particular houses or 

 towns within the territory of another species, though usually 

 without spreading. 



Orientalis is, for example, the common Cockroach of England, 

 but germanica frequently gets a settlement and remains long in 

 the same quarters. H. C. R., in Science-Gossip for 1868, p. 15, 

 speaks of it as swarming in an hotel near Covent Garden, where 

 it can be traced back as far as 1857. In Leeds, one baker's 

 shop is infested by this species ; it is believed to have been 

 brought by soldiers to the barracks, after the Crimean war, and 

 to have been carried to the baker's in bread-baskets. We have 

 met with no instance in which it has continued to gain ground 

 at the expense of orientalis. Americana also seems well estab- 

 lished in particular houses or districts in England. H. C. R. 

 (loc. cit.) mentions warehouses near the Thames, Red Lion and 

 Bloomsbury Squares, and the Zoological Gardens, Regent's 

 Park. It frequents one single warehouse in Bradford, and is 

 similarly local in other towns with foreign trade. 



Many cases are recorded in which germanica has been replaced 

 by flricntaUs, as in parts of Russia and Western Germany, but 

 detailed and authenticated accounts are still desired. On the 

 whole or ten falls seems to be dominant over both germanica and 

 americana. 



The slow spread of the Cockroaches in Europe is noteworthy, 

 not as exceptional among invading species, but as one more 

 illustration of the length of time requisite for changes of the 

 equilibrium of nature. It took two centuries from the first 

 introduction of orientalis into England for it to spread far from 

 London. Gilbert White, writing, as it would appear, at some 

 date before 1790, speaks of the appearance of " an unusual 

 insect," which proved to be the Cockroach, at Selborne, and 

 says : " How long they have abounded in England I cannot say; 



