32 Guide to Insects and Ticks 



Kabyl shepherds, laying its eggs, while flying, in the eyes, nostrils 

 and lips ; the larvae, when hatched, cause intense irritation of the 

 conjunctiva, and of the cavities and sinuses of the nose and 

 throat. The disease lasts about twelve days, and is known 

 locally as thim'ni. 



FLEAS AND PLAGUE. 



Plague or l^ubonic pest is a disease of the rat, communicated 

 from infected to healthy rats by fleas, of which Xcnopsylla chcoins 

 Eothsch. is the most important in tropical and subtropical 

 countries. On the death of an infected rat the fleas leave the 

 body, and if other rats are not available, will fasten upon man, 

 and may communicate the disease. In man bubonic plague 

 proves fatal in a large percentage of cases, and a marked feature 

 of the disease is the enlargement of the superficial glands, such as 

 those of the groin and armpit, into painful swellings or buboes. 



Another type of plague, known as pneumonic plague, affects 

 the lungs. The Manchurian epidemic of 1911 was of this type. 

 The infection in this case appears to have originated from plague 

 among the Mongolian marmots or tarbagans, Marmota hohac 

 Pallas, that are trapped by the Manchurian hunters for the sake 

 of their fur. The flea found upon the tarbagan is CaratophiiUns 

 silantiewi Wagn. 



In one of the table-cases in the middle of the floor of the Hall 

 there are shown selected specimens and enlarged models of the 

 tropical rat-flea, Xenopsylla cheopis Eothsch. (fig. 9), which, as 

 stated above, is most responsible for the spread of plague in 

 hot countries. The tropical rat-flea is found on several other 

 mammals besides the rat ; the hosts are mostly rodents, but 

 include a few shrews. This species of flea has been spread by 

 rats to such an extent that it is now found all over the world ; it 

 does not flourish, however, in cold climates. 



The model on the pedestal is that of a male, enlarged 200 

 diameters. The names of the parts of the insect, so far as external 

 features are concerned, are given in the coloured drawing below. 

 At the ends of the case are shown enlarged models of the head and 

 tlie hind end of a female tropical rat-flea ( x 250), so arranged 



