380 NEOTROPICAL PSELAPHIDAE 



Hamotus costaricensis, new species, Costa Rica. 



Hamotus alleei new species, Panama Canal Zone. 



Hamotus sandersoni new species, Panama Canal Zone. 



Hamotus castanalus new species, Panama Canal Zone. 



Hamotus aztekus new species, Mexico. 



Hamotus veracruzensis new species, Mexico. 



Hamotus veracruzensis fletcheri, new subspecies, Panama Canal Zone. 



Hamotus electrae, new species, Mexico. 



Hamotus thomasi new species, Colombia. 



Cercoceroides sternalis new species, Brazil. 



Tyrogatunus zeteki new genus and new species, Panama Canal Zone. 



Arhytodini 



Arhytodes achillei new species, Brazil. 



Clavigerinae 



Clavigerinae a subfamily of Pselaphidae, not a separate family. 

 Fustiger veracruzensis new species, Mexico. 



The names of undescribed species of Motschulsky are listed but have no 

 validity. 



There are 17 tribes, 141 genera, and 895 species of neotropical Pselaphidae. 

 These are discussed zoogeographically. The neotropics have over twice the 

 number of both genera and species as the nearctic region. Nineteen genera 

 are common to the Nearctic and Neotropical Regions ; five genera have species 

 outside the Western Hemisphere. 



The Neotropical Region is outlined with respect to Pselaphidae, and the 

 area placed at about 7,290,000 square miles, with three subregions: Central 

 American, Antillean, and South American. 



Vertical distribution and population by floating rafts are discussed. 



The number of species in each tribe, for each country of the neotropics 

 is given in tabular form. These data are combined with square miles of area to 

 work out Taxonomic Density. 



The fauna of Barro Colorado Island, Panama Canal Zone, is discussed 

 in detail and shown to have the highest taxonomic density known for the 

 neotropics, with its pselaphid elements showing much endemism and also a 

 strong South American influence. 



By means of a theoretical approach, involving a subspeciation factor, 

 community factor, competitive factor and a range factor, the total number of 

 species of neotropical Pselaphidae is estimated to be between 7000 and 14,000. 



The total neotropical population of individual pselaphids is estimated at 

 651,000,000 with a biomass of 2,604 kilograms. 



