THE MOUNTAIN ANTS OF WESTERN NORTH AMERICA.^ 



By William Morton Wheeler. 



Received September 12, 1916. 



The study of several collections of ants received from Professors 

 J. C. Bradley, C. F. Baker, T. D. A. Cockerell, C. C. Adams, S. J. 

 Hunter, Dr. W. M. Mann, Dr. R. V. Chamberlin, Mr. E. J. Oslar 

 and others and of my own collections made during several seasons in 

 Colorado, New Mexico, Texas, Arizona and Southern California, 

 and especially during the summer of 1915 in the Yosemite Valley and 

 at Lake Tahoe, California and in the Canadian Rockies, enables me to 

 give a much more consistent and comprehensive account of the dis- 

 tribution of the Formicidae of Western North America than was 

 possible heretofore. These collections represent two distinct faunas, 

 one of which belongs to Merriam's Lower and Upper Sonoran Zones 

 and comprises species of several neotropical and tropicopolitan 

 genera and subgenera, while the other, occurring at higher elevations 

 belongs to Merriam's Transition and Canadian Zones and is repre- 

 sented by species of the genera Monomorium, Solenopsis, Myrmecina, 

 Myrmica, Leptothorax, Aphaenogaster, Stenamma, Liometopum, Tapi- 

 noma, Prenolepis s. str., Lasius, Formica, Polyergus and a few sub- 

 genera of Camponohis {Camponotus s. str. and Myrmoturba). There 

 is some overlapping of the Sonoran and mountain faunas due to the 

 ascent of such forms as Pogonomyrmex occidentalis, Myrmecocystus- 

 mexicamis and a few species of Crematogaster, Pheidole and Solenopsis- 

 into the Transition Zone and the descent of a few species of Campo- 

 notus s. str., Myrmica and Formica into the Sonoran Zones. In the 

 following pages I have listed the known forms belonging to the Transi- 

 tion and Canadian Zones of Western North America and have added 

 descriptions of 32 new forms (three species, twelve subspecies and 

 seventeen varieties) which I have been able to recognize among the 

 recently collected material. I have not included any of our Pone- 



1 Contributions from the Entomological Laboratory of the Bussey Institu- 

 tion, Harvard University, No. 118. 



