ZOOGEOGRAPHY 



367 



Certain areas are better known than others. For example there are increas- 

 ing data showing considerable similarity of the pselaphid fauna of southern 

 Brazil and northern Argentina ; of northwestern Brazil and Colombia and Vene- 

 zuela; of Colombia and Panama; of southern Mexico and Guatemala. 



The discussion may be furthered by bringing horizontal area into the prob- 

 lems which beset us. 



