1911.] Pdrunkevilch, Index Catalogue of American Spiders. 5 



Simon, only about half of the species described belong really to the genera 

 under which they are placed. An attempt to place all species under the 

 proper genei'a would be futile. Not only the older descriptions of Walck- 

 enaer, Nicolet, C. Koch and Hentz give no clue to the correct generic 

 position of many of their species, but even the more recent works of Emerton 

 and Banks, indeed even some of the descriptions of F. Caml)ridge, one of 

 the most accomplished students of genera, do not mention some of the 

 indispensable generic characters. The descriptions of L. Koch and of 

 Count Keyserling are in that respect much better and I was able to place 

 correctly some of their species. Other species were placed by Simon from 

 the types still existing in the Paris Museum, by Strand from descriptions, 

 by Crosby, Chamberlin and Peckham from types and specimens contained 

 in the American collections. My private collection and that of the Ameri- 

 can Museum were of help to me in placing some of Banks's and Emerton's 

 species. With all that, a great number of species remains placed under 

 that genus to which they were assigned originally, although they do not 

 belong there any more. The result is, that do as I might I should not be 

 able to arrange the genera and species in such a way as to represent the 

 structural relation between them. The second objection is that such an 

 arrangement would require a special alphabetic list of genera with references 

 to pagination, making the use of the catalogue, already imperfect, still 

 more difficult. In view of these objections I arranged the genera alpha- 

 betically for each family, and the species alphabetically for each genus. 



'The genera accepted in this catalogue are in full accord with the defini- 

 tions ^"^'6" to them by Simon. This will be appreciated by every student 

 desirous to learn the relations between species and genera. No other work 

 has ever been published which shows such a wonderful grasp of the subject 

 and such extensive knowledge of forms as the Histoire Naturelle des 

 Araignees. As Thorell and Simon have pointed out, the original definition 

 of genera given by the older arachnologists cannot be used at present 

 without considerable limitations. Simon's researches, now extending over 

 half a century and embodied in the work mentioned, must necessarily be 

 made the starting point of every future investigation. A serious departure 

 from it would deprive a work such as this catalogue of the uniformity 

 without which it would be very defective. Some new genera have been 

 established since the publication of Simon's work and these have of course 

 been incorporated according to the definitions given to them by their 

 authors and with reference to the pul)lications in which they have appeared. 

 For the definitions and the complicated synonymy of all the remaining 

 genera the student is simply referred to Simon's work. This simplifies 

 the handling of the catalogue which is primarily a list and an index and not 

 a system. 



