100 THE FLEA [CH. 



bran and hide, so that the bag can be loaded as 

 cargo without anyone suspecting the presence of a 

 rat inside. M. rattus and its fleas, from the habits 

 of the host, are especially likely to be transported 

 in this way. Besides, many fleas are now dispersed 

 without their hosts in merchandise of various kinds. 

 They may travel great distances in these days of 

 rapid transport, though adult fleas, without a host 

 to feed on, generally die in about five days. But 

 larvae, which eat organic rubbish, and pupa3, which 

 do not eat at all, might arrive alive at the end of 

 a journey of well over a month. On arrival, they 

 would seek their true host, or the next best available 

 animal. Not having yet fed, and being newly emerged, 

 they might survive as long as a fortnight without a 

 suitable host. 



Fleas dislike damp breeding places, but dirty 

 carpets, chopped straw, old sacking, paper shavings, 

 and such-like rubbish suit them admirably. 



M. rattus is fond of making nests on grain bags 

 and in such sacking the larvae of fleas are often 

 found. Where trade is carried on in sacks and 

 gunny bags this means of distributing fleas and 

 plague should be kept in mind. 



Some rat-fleas, as we know, will feed on man 

 as well as on rats ; but their behaviour is rather 

 different when they feed on rats and on man. It 

 has been repeatedly noticed that the fleas were 



