98 



THE AMKIi/CAX MlsKIM J()rj{.\AL 



especially in the fall after houses wliicli li;i\ c Imch dosed during the summer 

 are reoix-ucd. LMr\al fleas liaxc iiiiiiit(iiii|)ted opportunity durinj^ the 

 sutnnier to develop into a(hilts which sometimes make a house literally 

 uninhaliit;il)le. Me;i> aic considered degenerate members of the Diptera, 

 the order to which flies and mos(|uitoes belong, and they are wingless, 

 winglessness often accompanying the parasitic state, perhaps through 

 disuse of these organs. That the flea lacks wings may make the si)read of 

 plague less rapid; the lack of flight powers, however, is counteracted by the 

 fact that fleas are carried long distances by their hosts. 



In the East, practically the only flea that gains access to the house is the 

 cat and dog flea {Ctcnoccplutlns canis), the human flea (PuJrx irriians) 

 Ix'ing rare. Measures for ridding a house of fleas must i)lan to attack not 

 only the adults but also the eggs and larva>. These are likely io be in the 

 dust of the animal's bed and in cracks and crevices al^out the house and 

 furnitiu'c. The remedy lies in making it ini))ossit)le for the eggs to develop 

 and the lar\;e to li\c in these places, in pro\'iding for the cat and dog sleep- 

 ing places that can be kept clean with all dust remo\-ed and burned. A 

 liberal use of j)yrethrum ])owdei' should be made in all places where it is 

 possible that flea eggs may have fallen. Kerosene or benzine are valuable 

 if milder means do not suffice while in extreme cases fumigation with hydro- 

 cyanic acid may be necessary. 



The rat flea (LannopHyUa chropis) is known as the "plague flea," but 

 both the hunuin flea and the cat and dog flea also live on the rat so that any 

 one of these may act as a carrier of the plague germ if they chance to travel 

 from a plague-infected rat. 



It has developed through a ft'W deaths in ( aliforiiia dii'eetly traceable 

 to handling ground squirrels that here too danger lies, that tin; plague 

 bacilli have reached these rodents probably from rats which use the s(|uirrels' 

 holes in fields. The discovery may mean the necessity of extermination 

 of the squirrels in infected regions. 



^«if^ 



,s.>^ 



