Abstract 



The methods of collecting both free-living and inquilinous Pselaphidae are 

 discussed. 



The preparation of these organisms for study is outlined with respect to 

 pinned specimens on points, whole-mounts for microscopic study, and special 

 techniques suggested for the study of special structures, such as foveae or 

 genitalia under very high magnification. 



The historical development of pselaphid taxonomy is sketched, with 

 especial emphasis on the Western Hemisphere. 



The comparative morphology of Pselaphidae is discussed with reference 

 to taxonomic and phylogenetic problems, especially emphasizing the paral- 

 lelisms and divergences between Pselaphidae and Staphylinidae. Special refer- 

 ence is made to the following: number and flexibility of abdominal segments; 

 male genitalia; maxillary palpi; tarsal segments and tarsal claws; antennae; 

 pubescence; foveae, especially vertexal, gular and sternal; a system of number- 

 ing sternal foveae is suggested and its phylogenetic significance discussed; 

 endoskeleton ; compound eyes. This section concludes with a definition of 

 Pselaphidae. 



A key to the seventeen tribes of neotropical pselaphids is given, follow- 

 ing which, each tribe is treated by a key to genera. The genera are variously 

 discussed, a key to species is given in each genus where feasible, and each 

 genus concludes with a catalogue of its species in which author, date of 

 description, geographic range, synonymy and genotype are listed. 



The several changes in the system of neotropical pselaphids, and new 

 genera and species follow: 



Juhinini 



Sebaga rafifrayi, S. notonoda new species, Panama Canal Zone. 



Sebaga scydmaenilla (Sharp) redescribed. 



Jubus terranus, J. chickeringi, J. turneri new species, Panama Canal Zone. 



Barrojuba albertae, new genus and new species, Panama Canal Zone. 



Euplectini (including Trichonychini) 



Fletcherexius new genus for macrodactylus (Fletcher). 



Group IV of Eurhexius divided into two sections. 



Eurhexius zonalis new species, Panama Canal Zone. 



Rhinoscepsis falli new species, Brazil. 



Rhinoscepsis dybasi new species, Mexico. 



Thesium barrocoloradoensis new species, Panama Canal Zone. 



Panaramecia williamsi, new genus and new species, Panama Canal Zone. 



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



Verabarolus subdendrus new genus and new species, Panama Canal Zone. 



Trimiopsis furcahs new species, Panama Canal Zone. 



(378) 



