366 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxvii. 



Department of Agriculture, Washington Cit}-; Dr. J. Fletcher, 

 Ottawa, Canada; Prof. C. P. Gillette, Fort Collins, Colorado; Dr. L. O. 

 Howard, Washington Cit}^; Kev. J. H. Keen, Masset, Queen Charlotte 

 Islands; Dr. A. Lutz, Sao Paulo, Brazil; Mr. G. S. Miller, jr., U. S. 

 National Museum, Washington City; Prof. A. P. Morse, Wellesley, 

 Massachusetts; Prof. Herbert Osborn, Columbus, Ohio; Mrs. A. T. 

 Slosson, Franconia, New Hampshire; Mr. J. O. Snyder, Stanford 

 Universit}', California; Mr. H. F. Wickham, Iowa City, Iowa; Mr. 

 D. B. Young, Newport, New York. 



The late Professors Harve}' and Hubbard also made valuable contri- 

 butions. I do not believe that too much credit can be given those 

 who are active collectors in biological work or who inspire active 

 accumulation of material. 



Having already become convinced of the inadequacy of the Taschen- 

 berg classification the work of Wagner came as no surprise. It, together 

 with the considerable accumulations of new material, made imperative 

 a revision of the American species. It was hoped this time to make 

 the work far more complete, embracing some comparative morpholog- 

 ical and emln-yological studies, which are much needed. The work as 

 laid out would have been sufficient to consume the time available for 

 such work during three 3^ears. Unforeseen contingencies made it 

 imperative that work on this subject for the time Ijeing should ])e con- 

 fined to one year or less. The logical course under the circumstances 

 being the completion of work already in progress, the following paper, 

 relating only to the taxonomy of the group, is presented as the direct 

 result of part of one year's work (1902). 



I have Dr. Kellogg to thank for a place to work during my stay at 

 Stanford University. 



The plates were all prepared by the author. 



The paper is based upon material in the United States National 

 Museum and all of the types are deposited in that Museum. The 

 names of hosts have been revised by Mr. Gerrit S. Miller, jr. Con- 

 cordance between the current nomenclature and the names used by 

 previous writers on fleas is established in the list of Siphonaptera of 

 the World (pp. 433 to 457), where the former will be found under the 

 special heading Hosts, and the latter are given after the references in 

 the synonymy. 



HISTORY. 



The histor}^ of the Siphonaptera, taxonomically speaking, begins 

 with the recognition of Pulex Irritans in 1740 and of PuJex penetrans 

 in ITGT. In the following j^^ears various scattering descriptions of 

 species and notes on anatomy and affinities were given by Bosc, Duges, 

 Westwood, Bouche, Haliday, and others, until 1857 when the Siphon- 

 aptera received their first systematic treatment at the hands of 



