32 STRUGGLE AMONGST ANIMALS 



not black and is not a beetle. It attains the length 

 of about an inch, and differs from the others in that 

 the females cannot fly. It swarms in enormous 

 numbers in the holds of ships, in basement kitchens, 

 and in dirty and damp places. This insect is supposed 

 to be a native of the far East and to have spread 

 through Europe gradually. Gilbert White, writing 

 in 1790, speaks of it as being an unusual insect at 

 Selborne, adding " how long they have abounded in 

 England I cannot say, but they have never been 

 observed in my house until lately." It was common 

 in London cellars so long ago as 1634, and no doubt 

 took a good deal of time to get to an inland village 

 like Selborne. The German cockroach, Phyllodromia 

 germanica, is much smaller, reaching about two- 

 thirds of an inch in length. It is paler in colour, 

 winged in both sexes, and is much more active than 

 any of the others, running quickly up vertical walls, 

 on ceilings, and even on surfaces as smooth as glass. 

 These little cockroaches swarm all over the rooms 

 they infest at night, and when disturbed they will drop 

 from the ceiling on the intruder's head. The German 

 cockroach is believed to have been originally a 

 native of the woods of central Europe, where it is still 

 occasionally found, but it took to invading houses, 

 especially bakehouses and breweries, and is now as 

 much a domestic parasite as the others. They are com- 

 mon in London restaurants, and in many of the large 

 blocks of flats, and have established themselves in 

 several parts of England. They are extremely tena- 

 cious of life and will survive even prolonged immer- 

 sion in water. In the United States, where the 

 species is known as the Croton bug, because its first 



