10 
Psyche 
[March 
west of General Trias, none of the stations in Chihuahua 
yielded more than a single colony. Many of the oak groves 
in Chihuahua, particularly those near the larger towns, have 
been denuded by wood-cutters. Despite this there are 
numerous areas where the groves are untouched. Those 
south of Parral are as extensive as any that the writer has 
encountered. Since apache will nest in at least three of the 
oaks present in this region, it follows that there are abund- 
ant nest sites available for it in central and southern Chi- 
huahua. Yet the incidence of apache in these groves is low. 
In many groves the writer failed to find any specimens of 
apache and the few colonies which were secured are the 
result of repeated visits to the station at which they were 
finally taken. It may be recalled that identical collecting 
procedure in the oak groves of southeastern Arizona often 
produced from three to ten colonies per station. 
The survey which gave the above records was carried 
south into Jalisco and Guanajuato and west through the 
Sierra Madre Occidental in Durango to the eastern border 
of Sinaloa. Except for the single record from Villa Ocampo, 
a small town five miles south of the Durango-Chihuahua 
border, no colonies of apache were taken south of the state 
of Chihuahua. The three southernmost records for apache, 
Villa Ocampo (Durango), China (Nueva Leon) and Monte 
Alto (Texas) are all near Latitude 26°. China lies about 
twenty-one miles to the south of the parallel, the other two 
stations lie a little to the north of it. Hence, there is a 
distance of at least one hundred and fifty miles between 
each of these stations and the Tropic of Cancer. The writer 
has repeatedly collected in the region between Latitude 26° 
and the Tropic of Cancer. The eighty-nine stations which 
have been visited extend from Tamaulipas through Nuevo 
Leon and southern Coahuila to the western border of Du- 
rango. Oaks were present at many of the stations and 
these oaks frequently contained arboreal ants. But the 
only record for apache coming from this region is the 
China record cited above. It is certain, therefore, that the 
incidence of apache south of Latitude 26° is even lower 
than it is in Chihuahua and it is probable that this ant is 
absent over much of the region between Latitude 26° and 
the tropics. 
