1955] 
Gregg — A New Pheidole 
27 
species is based represent nine separate colonies collected 
on July 24, August 12, August 16, September 18, and 
September 22, 1952. They were all secured by Dr. and 
Mrs. Creighton from the same place (type locality), and 
winged castes were present in the colonies obtained on 
August 12, September 18 and 22. 1 
Variation in type material: About one-third of the sol- 
diers have the vertex very smooth and absolutely devoid 
of sculpture save for minute piligerous punctures, the 
remainder showing exceedingly fine striations confluent 
with the rugae on other parts of the head. This delicate 
sculpture, however, does not reduce the brilliant surface 
of the vertex in the specimens to hand. Soldier mandibles 
may have the two apical teeth absent or nearly so, and 
give the appearance of having been worn down by long 
continued use. One soldier showed vestiges of the two 
lateral ocelli, and one colony contained 15 soldiers in which 
the postpetiolar conules were so reduced as to be nearly 
absent. Worker scapes just reach the occipital corners 
or very slightly surpass them. There are elusive differences 
in color among the many specimens seen, some being 
slightly darker in over-all tone, but these fluctuations are 
regarded as inconsequential. 
Affinities : This ant is closely related to members of the 
pilifera complex, and in fact runs out to this group in 
Creighton’s recent key (1950), but fails to fit any of the 
forms treated. Perusal of the accompanying tables (Table 
I and Table II) will help to distinguish the new ant, 
creightoni, from its relatives for the important diagnostic 
features have been emphasized, especially of the soldier 
caste. Of these, it has been found that the most valuable 
characteristics for separating creightoni from other forms 
of the pilifera group are, (1) its small size (except for 
artemisia), (2) the nature and distribution of particularly 
^ince this paper was submitted, Dr. A. C. Cole very kindly sent me 
a sample of Ph. creightoni containing four soldiers and numerous workers 
which he collected at Winnemucca, Nevada, elevation 4334 feet, on July 
8, 1954 (Cole Collection # 212). The specimens appear in every way 
to be conspecific with the types of the new species, and this opinion 
has been confirmed both by Dr. Cole and by Dr. M. R. Smith. 
