NO. 1361. REVISION OF AMERICAN SIPHONAPTERA— BAKER. 



463 



GEOGRAPHICAL DISTRIBUTION. 



"\^'itll our very incomplete knowledge of the oroup, any Itroud 

 generalizations as to distribution must be considered as merel}' tenta- 

 tive. At this stage, however, the following observations may be of 

 interest: 



I. The Palfearctic and Nearctic regions each possess a genus not 

 known to the other, the other genera being common to the two 

 regions. 



II. The order is very homogeneous north of the ecjuator, very 

 heterogeneous near to and south of it, South America furnishing the 

 greatest number of isolated types. 



III. Species peculiar to those regions have not j'et been described 

 from Central America, Polynesia, flapan, China, India, and South 

 Africa. Unquestionably all of these regions will furnish many pecul- 

 iar forms. 



IV. One species has been described from Arctic regions and one 

 from Antarctic regions. 



V. The genus Stephanocircm is represented by two species — one 

 Australian (on Dasyurus) and one South American (on " Ile^peromys'^^). 



VI. The genus Ilystrichopsylla contains two species — one from 

 Europe, the other from northeast America. 



VII. In America no species have been reported from the larger 

 proportion of our native mammals, including bats, raccoon, badger, 

 beaver, puma, muskrat, etc., though they all probably harbor fleas. 



VIII. The following genera are distinctly local in distribution: 

 VermipsyUa., Echidnophaga, Step/umoch'cus, Jfegapsy/la,, Hecto- 



psylla^ and Anomiopsyllus. 



IX. In tropical regions four species are nearly cosmopolitan: Ptdex 

 irritans, Ctenocephalus can is, Sarcopsylla penetrans, and Xestopsylla 

 gallinacea. The two former are also nearly cosmopolitan in temper- 

 ate regions. 



Statistics of families, genera, and species. 



