Zobgeographic and Statistical Considerations 



A complete analysis of the distribution of Pselaphidae in the neotropics 

 involves the Nearctic Region, and eventually all faunal regions since the 

 analysis would be global in its many implications. Moreover, we should need 

 some information on the palaeontology, ecology, and genetics of pselaphids 

 as well as data on palaeogeography. Only a small portion of this is available. 



Such an analysis is impossible in this paper for the reason that the neo- 

 tropical pselaphid fauna is imperfectly known, and its distribution even less 

 understood. Therefore my purpose here is to tabulate some suggestive data, 

 and suggest some problems for future solution. 



Table III 

 COMPARISON OF NEARCTIC AND NEOTROPICAL PSELAPHIDAE 



Tribe 



Faronini 



Pyxidicerini 



Jubinini 



Euplectini (s.l.) . . . 

 Brachyglutini .... 



Metopiini 



Batrisini 



Tychini 



Goniacerini 



Pselaphini 



Holozodini 



Hybocephalini . . . 



Ctenistini 



Tyrini 



Arhytodini 



Attapseniini 



Clavigerini 



Totals: 11 tribes 65 384 



17 tribes 141 895 



From this table it will be seen that the neotropics have all nearctic tribes 

 plus six tribes not found in the nearctic, over twice as many genera and over 

 twice as many species. Only the Faronini, Euplectini and Ctenistini are better 

 represented in the nearctic areas. Of these three, the ctenistines are possibly 

 truly better adjusted to the lower mean temperatures and lower annual rain- 

 fall, but the euplectine's slight superiority in nearctic species number is un- 

 doubtedly apparent rather than real. That is, the average minute size of 

 euplectine units makes their collection difficult. While the United States has 

 been very well collected relatively, floor sifting and Berlese sampling is just 

 beginning in the neotropics. The vastness of the unexplored areas, their slow 



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