ADDITIONAL STUDIES ON 
PSEUDOMYRMEX APACHE 
(HYMENOPTERA: FORMICIDAE) 
By William S. Creighton 
Department of Biology, City College, New York 
When Pseudomyrmex apache was described in this Jour- 
nal in 1952 (1), the writer called attention to the fact that 
the incidence of this ant appeared to be greatest in the 
mountains of southeastern Arizona and that the incidence 
seemed to decrease sharply in areas south of that region. 
Additional field work in northern Mexico during the spring 
of 1953^ has shown that this view is correct. Moreover, 
these studies indicate that the range of apache does not 
enter the tropics at all. This is a noteworthy distribution 
for a member of the genus Pseudomyrmex. The majority of 
the species in that genus are strictly confined to the Neo- 
tropical region and the few species which range into the 
southern United States are usually more abundant south 
of the Tropic of Cancer than north of it. The unique geo- 
graphical position of Ps. apache is, therefore, a matter of 
unusual interest. 
The new records for apache are presented below, together 
with a map showing the known range of this species: 
Texas: Arsarca Canyon, Chinati Mts., (4800') one colony 
Quercus grisea. 
Nuevo Leon : China (600') one colony in Prosopis juliflora, 
work done on a Guggenheim Fellowship. 
Chihuahua: 3 miles south of Encinillas (4900') one col- 
ony in Q. emoryi; 16 miles west of General Trias 
(5800') two colonies, one in Q. emoryi, the other in a 
deciduous oak (sp?) ; 23 miles south of Parral (5500') 
one colony in Q. santaclarensis ; 34 miles south of Par- 
ral (5800') one colony in Q. santaclarensis. 
Durango: Villa Ocampo (5700') one colony in Q. fusifor- 
mis or closely related species. 
It should be noted that, except for the two colonies taken 
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