COCKROACHES 33 



appearance in great numbers was associated with the 

 introduction of the Croton system of water-pipes in 

 New York, it has become the most abundant, estab- 

 lishing itself, probably because of its smaller size and 

 more active habits, in preference to the oriental and 

 the American cockroaches. The American cockroach, 

 Periplaneta americana, is a reddish-brown creature, 

 strong on the wing in both sexes, and attains a 

 huge size from an inch and a quarter to nearly two 

 inches. It has been called the ship cockroach, as it 

 is the insect most often seen by passengers, and 

 although originally a native of tropical or South 

 America, it has spread over the world probably with 

 trade, and has established itself in a good many 

 towns in this country, chiefly in warehouses. A 

 closely allied species, P. australasia, not quite so 

 long, although rather wider, and more brightly 

 coloured, has now acclimatized itself chiefly in 

 greenhouses in many parts of England. One or 

 two other exotic cockroaches occasionally appear in 

 England, and a green one, which comes with bananas, 

 has been reported from houses in South Kensington. 



In the Zoological Gardens the Oriental, the German, 

 and the American cockroach have all been thoroughly 

 established for years. The large American cockroach 

 infests the Reptile-house, the German species the 

 Small Bird-house and the Ape-house, and the 

 oriental insect is specially addicted to the Small 

 Mammals'-house and the keepers' rooms. I can find 

 no evidence that the members of the different species 

 attack one another, but they are very rarely found 

 in actual association. Obviously they find in their 

 respective haunts conditions that suit them well, 



