1955] 
Wilson and Broivn — Formica 
115 
obtusopilosa Emery 
= obtusopilosa alticola Wheeler (n. syn.) 
perpilosa Wheeler 
Species in the Sanguinea Group Proper 
In our study of sanguinea and relatives, we have been 
engaged chiefly with the Nearctic forms. It will be noticed 
that where Creighton recognized ten Nearctic species in 
the true sanguinea group, we retain only half that num- 
ber, and of these five names, we can recognize only two 
as representing solidly verified and distinct species: sub- 
integra and subnuda. The three forms curiosa, parcipappa 
and ivheel&ri were all described from very limited material, 
and all are close to, if not synonymous with, the extremely 
variable subintegra. All three are western in distribution, 
and significantly it is in the west that subintegra reaches 
its peak variability, in an area where a wide range of 
differing habitats is available to influence variation. It 
is also possible that these slave-makers respond in some 
way to the characteristics of the available slave species 
of Formica, which in general are more diverse in the 
western part of North America. 
As work on the sanguinea group progressed, we solicited 
the aid of several of our North American colleagues with 
respect to problems met. While comments and material 
received in the ensuing exchange were often very helpful, 
we have been surprised at the vigor of the opposition 
aroused by somje of our synonymic proposals. Unfor- 
tunately, the evidence for such opposed viewpoints did 
not match the conviction with which they were some- 
times expressed. Despite requests on our part for further 
particulars, we have received no evidence to indicate that 
anything is amiss with our synonymy. We are assuming 
that all important relevant data have now been forwarded 
for our consideration in the preparation of this paper. 
The couplet offered below will serve to separate workers 
of subnuda from those of subintegra. 
A. Gula completely bare of standing hairs in all of the 
workers of a nest series; dorsal petiolar margin 
