198 
Psyche 
[December 
During the summer of 1933 the writer had the opportun- 
ity of collecting in the La Sal Mountains in southeastern 
Utah, an excellent region of unusual scenic beauty. The area 
worked was in the vicinity of the Warner Ranger Station 
which is situated on the northwestern side of Mount Allen 
at an elevation of about 9500 feet. Most of the collecting 
was done at the upper edge of a sage brush area which 
covers a large part of the top of Wilson Mesa. At the ele- 
vation just mentioned the sage brush is stunted in size and 
occurs on exposed ridges between which there are valleys 
filled with aspen trees. In this aspen-sage brush associa- 
tion one of the most abundant ants is Formica sanguinea 
subsp. puberula Emery. Of the many colonies of this insect 
which the author examined one was unique in containing 
specimens of Formica microgyria subsp. rasilis Wheeler as 
slaves. In addition a second slave, Formica cinerea var. 
altipetens Wheeler, was present. This second slave need 
cause no comment since other forms of cinerea have been 
previously reported as enslaved by puberula. So far as I 
am able to determine, however, there is no previous record 
of the enslavement of any member of the microgyna group. 
It may be seen that there are two explanations for the 
formation of the colony just described. The simplest as- 
sumption is that the rasilis workers had been brought into 
the nest as a result of dulosis. On the other hand, since ras- 
ilis is known to be a temporary social parasite, it is possible, 
though not likely, that the colony might have arisen through 
the simultaneous entry of a female of puberula and one of 
rasilis into the original altipetens colony. A thorough ex- 
cavation of the colony lead to the finding of two females of 
puberula but no female of rasilis was seen. In this case I 
feel that it is permissible to utilize the negative evidence re- 
sulting from her absence and state that the rasilis workers 
had been secured through dulosis since, less than a hundred 
yards from the excavated nest, I subsequently found a 
puberula colony engaged in attacking a nest of the typical 
microgyna. The microgyna nest was built at the base of a 
