1954] 
Creighton — Pseudomyrmex apache 
11 
There are now enough records to show that apache oc- 
curs in a comparatively narrow band of territory, about 
twelve hundred miles long, which extends northwestward 
from the mouth of the Rio Grande River to southern Cali- 
fornia. Because of the skew of this band to the northwest 
it is difficult to give satisfactory northern and southern 
limits for the range of apache. If only latitude is considered 
the range runs from Lat. 33° 25' to Lat. 25° 48', a north- 
south extent of approximately 512 miles. But this method 
of delimiting the range is confusing, for it leaves out of 
account the fact that at any point along the east-west axis 
the width of the range is much less than five hundred miles. 
Indeed, in most places the band seems to be no more than 
two hundred miles wide and its maximum width does not 
exceed 370 miles. The distribution of apache throughout 
this long, narrow band is not uniform. The figures below 
show the total number of stations and colonies in each of 
the states where apache 
occurs. 
Stations 
Colonies 
California 
1 
2 
Arizona 
11 
39 
Chihuahua 
5 
10 
Texas 
3 
4 
Nuevo Leon 
1 
1 
Durango 
1 
1 
The very marked abundance of apache in the region near 
the southeastern border of Arizona is even more striking 
when it is considered that half of the ten colonies secured 
in Chihuahua came from a station in the extreme north- 
western corner of the state (Nogales Ranch) which is only 
about thirty miles south of the U. S.-Mexico border. Since 
the most favorable part of the range of apache appears 
to be the region at the northern end of the Sierra Madre 
Occidental, it is instructive to consider the environmental 
conditions in this area. 
The majority of the Arizona records for apache come 
from what Shreve (2) has called the ‘‘western xeric ever- 
green forest where oaks are dominant.” This association 
is closely similar to LeSeur's (3) '' santaclarensis consocia- 
tion” in Chihuahua. There seems to be no essential climatic 
difference in the two biomes, the principal distinction be- 
