1956] 
Creighton — Ephebomyrmex 
65 
of hairs are less regular in arrangement and much less 
conspicuous than the linearly-arranged lateral psammo- 
phores of some of the other species, but it certainly can- 
not be said that the gular pilosity of imberbiculus or 
pima is as scant as that of mayri. While our species of 
Ephebomyrmex do not have full beards, they certainly 
do have goatees, hence Wheeler’s distinction is one of 
degree, not of kind. There can be little question that 
when Emery stated in 1921 (12) that the subgenus 
Ephebomyrmex is an artificial group, he had the above 
facts in mind. Emery pointed out that neither the absence 
of a psammophore nor the presence of a toothed epinotal 
flange at the insertion of the petiole distinguish the 
members of Ephebomyrmex from certain intermediate 
species ordinarily assigned to the subgenus Pogonomyrmex. 
Emery cited the South American species silvestrii and 
brevibarbis in this connection but he could have mentioned 
the North American species huachucanus with equal pro- 
priety. The psammophore in both worker and female of 
huachucanus is transitional both in degree of develop- 
ment and position. The hairs which form it are fairly 
long and, for the most part, linearly arranged, but this 
line of hairs runs diagonally inward from the insertion 
of the mandible to a point at the middle of the head which 
is a little in advance of the rear border of the gula. This 
gives a V-shaped median psammophore which is quite 
unlike that of most species in the subgenus Pogonomyrmex , 
where the hairs of the psammophore are arranged in a 
line along the outer edge of the gula and turn in toward 
the center of the head at its rear edge. 
One can agree with Emery that the criteria which 
Wheeler used for the recognition of Ephebomyrmex are 
not well-chosen and one can further agree with him that 
substantial improvement in the situation will necessitate 
a better acquaintance with the sexual forms of this group. 
In this connection the writer would like to call attention 
to one interesting feature in the thoracic structure of 
the female of imberbiculus. The scutellum of the female 
of imberbiculus does not rise abruptly above the metano- 
