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Genus PULEX Linn. 



13. Pulex irritans Linn. This flea is widely distributed through- 

 out the world, and while essentially the human flea has been found 

 on many different species of animals and has frequently been en- 

 countered on rats. A very large number of specimens have been 

 taken off rats in San Francisco, Cal. 



Genus LOEMOPSYLLA Rothschild. 



14. Loemopsylla cheopis Rothschild. This is the common rat flea 

 in tropical and subtropical countries. It has also been found in 

 seaports of the temperate zone, where it has been brought by ship 

 rats. Ninety-eight per cent of the rat fleas in India are of this 

 species. It has been found in Australia, where it was described by 

 Tidswell under the name of Pulex pallidus. In the Philippine Islands, 

 where it was described by Hertzog as the Pulex pliilippinensis. It 

 has been found in Brazil, where it was described by Baker as Pulex 

 brasiliensis, and Tiraboschi has found it in Italy, where it has been 

 described as the Pulex murinus. This flea has been frequently 

 found on man in India. 



Genus CTENOCEPHALUS Kolenati. 



15. Ctenocephalus canis Curtis. This is the common dog flea 

 found in many parts of the world and is frequently taken off rats. 



16. Ctenocephalus fells Bouche. This is the common cat flea and 

 is also a widely distributed species. Frequently taken off rats. 



Genus CTENOPSYLLUS Kolenati. 



17. Ctenopsyllus musculi-Dug6s. In England this flea is commonly 

 found on the domestic mouse. It has a wide distribution and has 

 been found on rats and mice in Europe, South Africa, India, Aus- 

 tralia, Mexico, and other places, and has been taken off Mus norve- 

 gicus, Mus rattus, and Mus musculus in San Francisco, Cal. 



Genus NEOPSYLLA Wagner. 



18. Neopsylla bidentatiformis Wagner. This flea has been taken 

 off Mus norvegicus in the Crimea. 



Genus HOPLOPSYLLUS Baker. 



19. Hoplopsyllus anomalus Baker. This is one of the common 

 groundsquirrel fleas of California and has been found on Mus norve- 

 gicus in San Francisco and Palo Alto, Cal. That these squirrel fleas 

 are occasionally found on rats is interesting from the fact that 

 plague has been demonstrated both in rats and the ground squirrel 

 in California. 



