18 
Psyche 
[March 
would expect to find even in a nest series of exsectoides. 
It must be remembered that the types of the supposed 
hesperia came from Colorado Springs. 
To return to the species of greatest concern in this paper, 
Creighton believes that opaciventris should stand as a well 
defined form and not as a subspecies of exsectoides where 
it was placed by Wheeler in 1913. Emery had originally 
described it as a variety of the same in 1893. Creighton’s 
treatment may be the wiser, but from the descriptions of 
differences among the females as noted above, and the 
workers which also differ only in the greater pilosity of 
opaciventris, it may be necessary to return to Wheeler’s 
proposal. The differences enumerated, at best, seem to be 
rather slight, hence it would appear possible to consider 
the two ants as very closely related with opaciventris a sub- 
species of exsectoides. Moreover, the ranges of these in- 
sects, though heretofore regarded as far apart, actually 
overlap, but the degree of overlap is at present very un- 
certain. Creighton gives Nova Scotia to Georgia and west 
to Wisconsin and Iowa as the territory of exsectoides, 
while opaciventris is a Rocky Mountain form. Specimens of 
both of these species are present in my collections from the 
vicinity of Boulder, Colorado, the former from foothills at 
about 7500 feet, and the latter from the plains at slightly 
over 5000 feet. Thus we have to revise westward our con- 
ception of the range of exsectoides, and the range of opa- 
civentris is now known to extend to lower altitudes and 
perhaps eastward on the plains. It may be found, when 
more material is gathered, that the two forms intergrade, 
and if so they will have to be classed as subspecies. 
Formica ulkei should stand alone as a distinct species. 
The ranges of ulkei and exsectoides are known to overlap 
in northern Illinois and Indiana, southern Wisconsin, and 
Iowa, but the ants remain morphologically distinct even 
though the nests of each are practically identical in ap- 
pearance. I have specimens of ulkei and exsectoides col- 
lected within a few hundred feet of each other at Palos 
Park, Illinois, and there is not the faintest indication of 
intergradation. In the case of these two species, then, we 
have nothing to show that one could be a subspecies of the 
