A SYSTEMATIC ACCOUNT OF THE GRASSHOPPER MICE. 



By N. HOLLISTER, 



Assistant Curator, Division of Mammals, United States National Museum. 



INTRODUCTION. 



The nomenclatorial history of the Grasshopper Mice, or Scorpion 

 Mice, begins with 1841, when Maximihan, Prince of Wied, in his 

 Reise in das innere Nord-America, described Hypudaeus leucogaster 

 from what is now the State of North Dakota. Coues, in the Mono- 

 graphs of North American Rodentia, 1877, recognized two species, 

 Hesperomys iOnychomys) leucogaster (Maximihan) and Hesperomys 

 (Onychomys) torridus Coues. The only definite synopsis of the 

 group since that date was pubhshed by Merriam in 1889,^ In this 

 paper Onychomys was for the first time properly diagnosed and given 

 full generic rank. Four species and one subspecies were recognized. 

 The latest list of North American mammals,^ pubhshed in 1912, in- 

 cludes 19 named forms, 11 of which stand as full species. Four sub- 

 species have since been described. 



In the present revision of the genus two names are placed in syn- 

 onymy, one is revived and one new subspecies is described. These 

 changes leave the total number of recognized forms at 23, a net in- 

 crease of 4 since 1912. While the number of races has been increased, 

 the number of actual species has been reduced to two, the leucogaster 

 and torridus of Coues's report of 1877. Such changes appear to be 

 the inevitable result of study of the magnificent series of American 

 mammals now preserved in our museums, particularly the collection 

 of the Biological Survey. With a suite of specimens such as these 

 collections afi'ord, direct intergradation between many supposedly 

 distinct species is apparent, and with the increase in the number of 

 geographical races a decrease in the number of recognizable species 

 is to be expected. 



1 North Amer. Fauna, No. 2, pp. 1-5. Oct. 30, 1889. 



2 MiUer, BuU. 79, U. S. Nat. Mus., pp. 126-129. Dec. 31, 1912. 



Proceedings U. S. National Museum, Vol. 47— No. 2057. 



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